Template Customisation help needed

Hi, I hope someone can help me.
I’m customising a wordpress template to look like my website:
http://www.thedigitaldemons.com/beta2/index.shtml

the blog is here: http://www.thedigitaldemons.com/marc

Basically I want the sidebar and the posts to be centered (so under the header) with the sidebar left aligned and the posts right aligned.

I think I’m nearly there on this one, but its a bit complicated as I’ve combined the blog stylesheet with the webpage one…
http://www.thedigitaldemons.com/beta2/stylee.css

I also need to sort out the white spacing between the posts..(might be a margin/padding issue)

Thanks in advance for help,
I can explain further if my coding is too hard to work out
Cheers
Marc