Aligning forum body and logo

[Miller85]

I realise it's probably a really simple question but I have extremely limited coding skills and similarly have been unable to find anything through searching here. If I've missed an obvious thread then apologies...

Anyway, a friend sorted the basic style for my forum (http://forums.airsofters.co.uk) when it was released. He's since "disappeared" and now we're looking at restyling the forum to look a bit more interesting. The problem is now the forum stretches to fill the browser window. Ideally we'd like it centred, with an underlying graphic visible on one side.

Essentially, the aim is something like this:

http://entropiaforum.com/forums/

Centred logo, centred body, background graphic.

Through really awful hit and miss methods we've at least got the idea of a background graphic in place:

http://forums.airsofters.co.uk/index.php?styleid=3


That's clearly a long, long way from ideal though as everything is completely buggered. Any input on how we can achieve the desired look would be great, thanks

David