I am trying to figure out where, or what code I can edit to accomplish the following.

At the site http://www.oldpostbbq.com I am trying to get a white background within the main content area (The white bars with <H1> Tags are in the perfect spot, and are an example of the area I am trying to fill). I have ftp every style sheet, and edited main index code, and I can't figure it out. Any help would be appreciated. using Firebug you can see the code, and I can provide any CSS files needed. Thanks