You should do more research before you spend money on a laptop. Research is free and easy and would have told you that this laptop has more video power than CPU power. Replacing a CPU in a laptop is complicated, voids your warranty, and require skill and patience to complete.
Do you really need to upgrade it? I have this laptop and I'm completely fine with the processor. Really, what are you doing that it's too slow for? And you can always Overclock it easily. Check my review thread for more information.