Windows 7 doesn't support much more than clicks, zoom, and scrolling on the Magic Mouse so I'm not sure what you are looking for.
You should still be able to download the Windows 7 drivers
here.
I just installed the Boot Camp Drivers in my dedicated (Not a Boot Camp Mac) Windows 7 computer from my Mac OS X 10.6 Boot Disk and let it install all the drivers. I then let Apple Software Update update the Drivers to 3.1 and 3.2.
I've had no problems with the Magic Mouse at all.
However you can try the drivers from the link above and let us know if they do the trick for you.