You can download the latest bootcamp driver package (6.0.6201.0?) and get the drivers from that. There was also an update via Apple Software Update for the new 'Magic' devices including the keyboard.
Here's a solution to the keyboard not working...
"You have to go to "Device Manager" (right click on Start: Device Manager option), at the HID leaf (that stands open 'cause of a driver error), simply uninstall and delete the wrong driver. Magically everything works fine, and the wireless keyboard will be reported on the Keyboards leaf of the Device Manager."