Copy Wordpress Installation To A New Existing Blog

We have an existing wordpress blog. It's a special version of wordpress (semiologic) and we want all posts and comments, headers, and the exact same settings copied over to a new blog. The new blog is currently already installed (just a vanilla install of wordpress 2.6 (latest version prior to 2.7) with plugins installed. Your job is to take all the comments and posts, the header, and pages and copy into the new blog. You have to preserve the EXACT paths existing in the source blog to the destination. eg. If there was a post at [login to view URL] Then you need to make sure this is exactly the same at the destination blog. All other settings of wordpress, need to be preserved as well. Once you are all done we will actually replace the version you have created by overwriting the existing one, so this is why it's vital that all the url's, etc are identical. Semiologic does add extra tables and possibly columns to the wordpress database, so you need to make sure you remove these so it works with the vanilla install of wordpress. You will also be asked to make some minor changes to a theme (make the colours more in line with our header image, etc). Provided you know php, wordpress, and some CSS, we believe this will be straight forwarf for you to do.