Counter Strike Source on MBP

I'm new to this forum and macs in general but it is about that time for an upgrade. I currently have a Dell inspiron 5100 2.8P4 with a ati 7500 Radion Mobility card(64) 1 Gig Ram. I am looking for a laptop that will be able to run both games and software with ease. I have been doing a little research online and have come across MBP. I also learned that it can boot both windows and the standard Mac os. Does anyone know how Counter-Strike Source will run on this machine? Ive heard mixed stories about the graphics and would like some clarification. A possible frames per second count? Overheating issues? Anything at all?
Id like to get the
BPG 2.6 4 gig 15' model.
Any help would be appreciated. Thanx in advance.