Theme Question

I have a site that is running the Classified Ads site. I am implementing the Auction Theme on a new domain. I would like the Auction site to have much the same look and feel of the site. Is there a quick, down and dirty way to just copy files and not have to enter everything again? Could you tell me which files I can just copy over and the rest I can manually change. Most of the changes are the footer & Header but I don’t want to just copy those if it will put other things out of wack. Any help that will save time would be appreciated!