I dont think you can convert a integrated video into the quadro.. from what I understand you can convert the 6800 to a quadro by soft modding.. I have one and looked into it and never got around to doing it. Also you may want to purchase a new video card since integrated video suck anyhow. sounds like a nice rig, make sure you have a pci-x16 slot before you go card shopping, as I doubt it would have a old AGP slot.

g'luck