NVIDIA driver (how to get 6800GT)?

Your current graphics are onboard (integrated with motherboard).The integrated graphics that you currently have are comparable to the 7 series so you may already be ok to play the game. However, the 6800GT is a graphics CARD (not integrated) and is more powerful than your 7150M graphics. You may need to upgrade to a 6800 graphics card if possible for your laptop (although I'm thinking you can't).