Graphics card driver problems

I recently purchased WoW Cataclysm and the fps during game play isn't ideal. I soon thought of seeing if an update for my MBP's graphics card (NVIDIA GeForce 9400M) was available. Nvidia suggest to download CUDA as well for optimal results which worked. I soon found an updated driver for it and attempted to install but received error message "This computer will not support this NVIDIA graphics solution." What confuses me is I provided the correct specs of my card and OSX version. What can be done and will a driver update even improve my gaming performance. I do not know much about Macbooks or computers in general so I do not know what to do or even what to look for. Thanks

Specs of my comp:
late 2009 15' Macbook Pro 2.54 GHz Intel Core 2 Duo 4GB
graphics card:NVIDIA GeForce 9400M
if any other information needs to be provided I'll gladly post it.