I don't know anything about the 2006 model, but the 2008 has a 300w? limit on the pci-e bus.. and that card draws ~197w, so on the 06 model, I would say probably not a good idea especially with another card
Im not sure on this but I think you can run it under windows only
oops sorry I didnt see that it was a 2006 model... hmm I think it should still have enough Watt to play it though. But not too sure about the pci-e 2.0 card works on a 1.1 slot...