Have the drivers for your Macbook Installed correctly on the Windows Side?
Go into Device Manager and Confirm this. One of the Mac OSX Install Discs that comes with the machine should Auto-run a bootcamp drivers installed upon inserting it into the cd drives. Follow the onscreen instructions and it will install of the the compatible drivers and Utilities for the Graphics card on the system. Other than that, check ou the Nvidia website to see if they have any advanced graphic utilities for the Macbook.
I doubt you will find anything...this is the reason why i build my own PC's and run windows natively if i want a gaming machine. Mac Limits your options far too much.