Here's one that's made for carrying the spare on a 2" receiver. This one doesn't fold down though. It's a little pricey too, but you could probably find one cheaper. Your local auto parts store could probably get you one. Check Autozone, Advance Auto, Pep Boys, etc.
http://www.etrailer.com/p-c31006.html
http://www.etrailer.com/p-c31006.html