use image for menu

I cannot figure out how to use my two images for the menu navigation.

I have one image I want to use as the background, and another I want to use as the hover and active page.

I am working on making a client's website using Wordpress. Currently, I just use static html.

I cannot figure out how to over ride the Atahualpa theme options for the menu. I have looked at other posts with some example CSS, but it just has not worked.

The current static website is http://www.mpbc-indy.org. I want the menu for the Atahualpa theme to look like this menu.