:xoutpost: and :welcome: to the Busted Window Regulator Club!
Here is the article on removing the door panel and replacing the broken regulator:
http://www.xoutpost.com/articles/x5/e...nt-bmw-x5.html
If you are out of warranty, and have an extra sent of hands, you may want to replace the regulator following the DIY in the article I linked. The part will run you just over $100USD. You will pay over $500USD for the dealer to replace it.