I've my wordpress install at localhost/ and my joomla install at localhost/s .

The code for my login form for wordpress is

<?php
/**
 * @package   gantry
 * @subpackage widgets
 * @version   1.0 March 15, 2011
 * @author    RocketTheme http://www.rockettheme.com
 * @copyright Copyright (C) 2007 - 2011 RocketTheme, LLC
 * @license   http://www.gnu.org/licenses/gpl-2.0.html GNU/GPLv2 only
 */ 

defined('GANTRY_VERSION') or die();

gantry_import('core.gantrywidget');

add_action('widgets_init', array("GantryWidgetLoginForm","init"));

class GantryWidgetLoginForm extends GantryWidget {
    var $short_name = 'loginform';
    var $wp_name = 'gantry_loginform';
    var $long_name = 'Gantry Login Form';
    var $description = 'Gantry Login Form Widget';
    var $css_classname = 'widget_gantry_loginform';
    var $width = 200;
    var $height = 400;

    function init() {
        register_widget("GantryWidgetLoginForm");
    }

    function render_title($args, $instance) {
        global $gantry;
        if($instance['title'] != '') :
            echo $instance['title'];
        endif;
    }

    function render($args, $instance){
        global $gantry, $current_user;
        ob_start();
        ?>

        <?php if(!is_user_logged_in()) : ?>

            <form id="form-login" action="<?php echo wp_login_url(get_bloginfo('url')); ?>" method="post">
                <fieldset class="input">
                    <p id="form-login-username">
                        <input id="modlgn_username" type="text" name="log" class="inputbox" alt="username" size="18" value="<?php _re('Username'); ?>" onfocus="if (this.value=='<?php _re('Username'); ?>') this.value=''" onblur="if(this.value=='') { this.value='<?php _re('Username'); ?>'; return false; }" />
                    </p>
                    <p id="form-login-password">
                        <input id="modlgn_passwd" type="password" name="pwd" class="inputbox" size="18" alt="password" value="<?php _re('Password'); ?>" onfocus="if (this.value=='<?php _re('Password'); ?>') this.value=''" onblur="if(this.value=='') { this.value='<?php _re('Password'); ?>'; return false; }" />
                    </p>
                    <p id="form-login-remember">
                        <input type="checkbox" name="rememberme" class="checkbox" alt="<?php _re('Remember Me'); ?>" />
                        <label class="rememberme"><?php _re('Remember Me'); ?></label>
                    </p>
                    <div class="readon"><input type="submit" value="<?php _re('Login'); ?>" class="button" name="submit" /></div>
                </fieldset>             
                <ul>
                    <li>
                        <a href="<?php echo wp_lostpassword_url(); ?>"><?php _re('Forgot your password?'); ?></a>
                    </li>
                    <?php if(get_option('users_can_register')) : ?>
                    <li>
                        <a href="<?php bloginfo('wpurl'); ?>/wp-register.php"><?php _re('Register'); ?></a>
                    </li>
                    <?php endif; ?>
                </ul>               
            </form>

        <?php else : ?>

            <form id="form-login" action="<?php echo wp_logout_url(get_bloginfo('url')); ?>" method="post">
                <fieldset class="input">

                    <div class="user-greeting">
                        <b><?php echo $instance['user_greeting']; ?> <?php echo $current_user->display_name; ?></b><br />
                    </div>
                    <div class="readon"><input type="submit" name="Submit" class="button" value="Log out" /></div>

                </fieldset>
            </form>

        <?php endif; ?>

        <?php 

        echo ob_get_clean();

    }

The code for my joomla login form is

<?php
/**
 * @version     $Id: login.php 303 2010-01-07 02:56:33Z joomlaworks $
 * @package     K2
 * @author    JoomlaWorks http://www.joomlaworks.gr
 * @copyright   Copyright (c) 2006 - 2010 JoomlaWorks Ltd. All rights reserved.
 * @license     GNU/GPL license: http://www.gnu.org/copyleft/gpl.html
 */

// no direct access
defined('_JEXEC') or die('Restricted access');

// OpenID stuff (do not edit)
if(JPluginHelper::isEnabled('authentication', 'openid')){
    $lang->load( 'plg_authentication_openid', JPATH_ADMINISTRATOR );
    $langScript = '
        var JLanguage = {};
        JLanguage.WHAT_IS_OPENID = \''.JText::_( 'WHAT_IS_OPENID' ).'\';
        JLanguage.LOGIN_WITH_OPENID = \''.JText::_( 'LOGIN_WITH_OPENID' ).'\';
        JLanguage.NORMAL_LOGIN = \''.JText::_( 'NORMAL_LOGIN' ).'\';
        var modlogin = 1;
    ';
    $document = &JFactory::getDocument();
    $document->addScriptDeclaration( $langScript );
    JHTML::_('script', 'openid.js');
}

// Get user stuff (do not edit)
$usersConfig = &JComponentHelper::getParams( 'com_users' );

?>

<div id="k2ModuleBox<?php echo $module->id; ?>" class="k2LoginBlock <?php echo $params->get('moduleclass_sfx'); ?>">
    <form action="<?php echo JRoute::_( 'index.php', true, $params->get('usesecure')); ?>" method="post" name="login" id="form-login" >

        <?php if($params->get('pretext')): ?>
        <p class="preText"><?php echo $params->get('pretext'); ?></p>
      <?php endif; ?>

      <fieldset class="input">
        <p id="form-login-username">
          <label for="modlgn_username"><?php echo JText::_('Username') ?></label>
          <input id="modlgn_username" type="text" name="username" class="inputbox" alt="username" size="18" />
        </p>
        <p id="form-login-password">
          <label for="modlgn_passwd"><?php echo JText::_('Password') ?></label>
          <input id="modlgn_passwd" type="password" name="passwd" class="inputbox" size="18" alt="password" />
        </p>
        <?php if(JPluginHelper::isEnabled('system', 'remember')) : ?>
        <p id="form-login-remember">
          <input id="modlgn_remember" type="checkbox" name="remember" class="inputbox" value="yes" alt="Remember Me" />
          <label for="modlgn_remember"><?php echo JText::_('Remember me') ?></label>
        </p>
        <?php endif; ?>

        <div class="readon"><input type="submit" name="Submit" class="button" value="<?php echo JText::_('LOGIN') ?>" /></div>
      </fieldset>

      <ul>
        <li><a href="<?php echo JRoute::_( 'index.php?option=com_user&view=reset' ); ?>"><?php echo JText::_('Forgot your password?'); ?></a></li>
        <li><a href="<?php echo JRoute::_( 'index.php?option=com_user&view=remind' ); ?>"><?php echo JText::_('Forgot your username?'); ?></a></li>
        <?php if ($usersConfig->get('allowUserRegistration')): ?>
        <li><a href="<?php echo JRoute::_( 'index.php?option=com_user&view=register' ); ?>"><?php echo JText::_('Create an account'); ?></a></li>
        <?php endif; ?>
      </ul>

      <?php if($params->get('posttext')): ?>
      <p class="postText"><?php echo $params->get('posttext'); ?></p>
      <?php endif; ?>

      <input type="hidden" name="option" value="com_user" />
      <input type="hidden" name="task" value="login" />
      <input type="hidden" name="return" value="<?php echo $return; ?>" />
      <?php echo JHTML::_( 'form.token' ); ?>
    </form>
    </div>    

I would like it to ensure that once the user clicks the login button on my small wordpress page together with his user and pass , the consumer and pass should get posted to joomla for login purpose and user ought to be drenched into joomla rather than wordpress . The standard login url for joomla is localhost/s/index.php?option=com_user&view=login&Itemid=204 .

This issue was somewhat addressed at Diverting WordPress login and register links to Joomla but didnt assist me to much .