I'm focusing on a joomla 1.5 site. I've been requested to include oclick occasions to the peak level nav for google event monitoring like so

I can not see anyway to get this done within the joomla admin. I understand in jquery I possibly could make use of the append command to include it although not sure how you can add this with mootools.

can somebody point me within the right direction?

Consider the class from the elements within the top level nav, then u could make a move super easy like:

window.addEvent('domready', function(){ //when the DOM is ready

  $$('.class-name').addEvent('click', function(evt){
    /* your event tracking, knowing that 'this' is the current .class-name element */  
  }); 

});