Web Design

I am creating a web site at the moment and I am having trouble. I made some simple buttons in by using the Rollover Image command in Dreamweaver. (Works the same as the bar above – Home, Articles goes blue once rolled over).

My problem is I want the Second/Rollover image to stay once it has been clicked. (As above- the page you are on is highlighted). Does anybody know a simple solution to do this or am I better off starting it from scratch. I am looking to do this in the Template.