1) Cough up a few hundred dollars, a SuperDrive, a CD-RW, and some hard disk space
2) Buy Windows 7
3) Launch Boot Camp Assistant
4) Do the stuff you need to do
5) Use the driver disk that Boot Camp Assistant burned
6) Get Kaspersky or eset on your computer
7) Download steam
8) Appreciate life
Here's winebottler for mac OS X. It's for intel graphics card only though. (try it without intel though)
http://winebottler.kronenberg.org/
If it doesn't work, sorry then.
lol WineBottler uses very outdated Wine packages, use loving WineSkin