Nav Bar & Rollover Help Needed Please!

I created a nav bar in Dreamweaver MX '04 using the nav bar object. I wanted
to create a second nav bar on the same page but it won't let me do that. (Why
not??) So then I decided to create the second nav bar using rollover buttons;
however, the rollover buttons appear to offer only two states ('original
image' and 'rollover image'). I would like to have a third state -- an onclick
state -- as they offer in the nav bar object. (From reading the threads about
nav bars, it sounds like it would be best if I got rid of the nav bar object
and simply used rollovers.) SO, I guess my question is: how can I add an
onclick state to a rollover button?? (Also, I am new at this and am building
this site from scratch. I'm a bit overwhelmed by all the different ways to lay
out a page; using <div> tags, tables, layers, etc. Any suggestions as to the
best technique for laying out a page and creating a rollover/nav bar such as
this?)
Thanks very much for your help.