I think you can have both in. But this makes only sense when you have more monitors connected. And I would say - more than two because these cards all support two monitors already.

This is the exact name that "about my Mac" tells me: ATI Radeon HD 2600. It has 256 MB VRAM. Be a bit specific on those or verify first when you by another card or version whether it works on Mac. I am still on 10.5.8 btw, just in case this is something you want to know too.

One day your ship comes in - but you're at the airport.