Wordpress really is not meant for anything other than a blog. Some extensions have tried to make it into a CMS, but it still pales in comparison to the competition. ExpressionEngine is the absolute best, but you have to pay $99, with a 40 buck annual fee.
I'm not too sure what will happen if you try to transfer everything. I know EE has a function to transfer stuff from Movable Type blogs, but some people have pain with it. Check out the
EE site.