Full Force Menu

I would like a site I’m building (lgbtlovestories.com) to have a full-force menu, (i.e. the menu should go from left page edge to right page edge). The template was built with Artisteer, and while it’s a pretty good design program, it is not all-encompassing. Through Artisteer it allows R,L, & C justification, but not full-force.

I haven’t built a site in a while, so I’m a little rusty.

Thanks so much in advance for any help.