Increase post area

Hi. My blog is http://noncollective.com/

I would like to increase the width of my post area. I’m currently uploading the images slightly bigger than the size of the post area that’s how wide I would like to go as you can see from this screen shot. http://img116.imageshack.us/my.php?image=picture6up2.jpg

Many Thanks. David.

Style.css:
http://wordpress.pastebin.ca/772414

Header.php
http://wordpress.pastebin.ca/772419