Noobie Styling Problems

Hi Everyone,
Hope some of you experts out there can help, I’m new at wordpress and am trying to style up a blog to match the rest of our site but I’ve got a problem with the layout of the main content and sidebar, I’ve put a wrapper div around all the content to centre it with a fixed width and added a container div around the post content so I can float this left and float the sidebar right for a two col layout, but when I go into the comments area the sidebar seems to have moved inside the container div breaking the layout and I can’t figure where this comes from, any pointers would be great.

http://talkingdesigntesting.net.helmserver.co.uk/tdl/blog/