Can't center page posts

Site URL: http://osrebirth.dreamhosters.com/

Hi, I’m having trouble getting my posts to display correctly. Basically I would like them to be about 700px wide, with no metadata shown. When I put this in my stylesheet, there is still a wide blank space on the right of the post content that wont disappear. This is causing the content to be shifted to the left.

How can I rectify this?

Currently this is what I have in my CSS:

.entry-meta {
	display: none;
}

.single-post #primary {
  margin-right: 0;
  width: 100%;
}

I’m trying different things like adding padding values to the left side, but it’s not helping. I can’t seem to find the code for the empty metadata area, even with firebug.