Graphics Card for Mac PRO 3 1

My Old geforce 8800 died, so I have to upgrade to another card.
I was thinking about EVGA GeForce GTX 570 HD 1280MB PhysX
or ati 5770.
I'll be running Cs6 and Cinema 4d.
Do I have to do a lot of hacking to get the gtx up and running with Mountain Lion?
Is this the right Gtx Card for me EVGA GeForce GTX 570 HD 1280MB PhysX?

Thomas