Yes, you would experience better performance by running it in a Boot Camp partition.
However, given your video card, I doubt you will have a good chance at running Skyrim smoothly. The requirements on your link state VRAM to be at least 512MB, which your card doesn't have.
Purchasing a newer stock NVIDIA Graphics card after updating your Mac to a newer version of OS X (10.8+) is what I would recommend. See this link: http://forums.macrumors.com/showthread.php?t=1440150