Had you posted in page layout changes, you may have received an answer by now. While css is very powerful. What you are wanting to do would be done by manipulating the placement of the divs in the tpl_header.php file.

Get yourself a copy of firefox with the web developer, firebug, and html validator addons. They'll help you see what needs to be moved.

Furthermore, as you hit refresh waiting for attention, you can look at the bottom of each thread for links to similar questions that may have been answered in a way that will help.

And... whilst waiting, please read the do's and don'ts for posting. You'll be pleased with the results if you follow those guidelines.