Hmm... just off the top of my head, but something you could try: Make the containing div relative, like you were saying, put the nav (after all the content) in that div, but positioned absolute at top/left=0px/0px, but have a blank div, floated left, at the beginning of the content to "clear out" the space for it (as the absolute div would overlay anything behind it). Granted, you'll want to test it, as I think absolute positioning inside a relative div is one of those spotty-supported browser issues.

You can also just make a description meta-tag on the page, which many search engines will display under the search listing. It makes your search listing look a lot cleaner and more professional.