Take a look at what I did which still isn't going to achieve what you want in a menu system.

I took the whole picture and set it as the background image.
Then overlayed the buttons, they are slightly off so you can see them. Can be adjusted in the css file using the margin left.
Problem is your background has the buttons on it.
If your background wasn't merged with the buttons you could then overlay the buttons and when clicked on
could be replaced with a button that has just an outline and no lettering or something.

You be better off redoing your menu system.

Sometimes it's better to make several different parts and saving them as seperate files psd gif and/or jpg.

The other thing you could try is to map the bkgrd.jpg so when someone hoovers over the mouse changes and it's clickable.
