If you read Adobe Site about GPU support you will read you can not mix display adapters. It is posible to hook all three of your displays to your 6970.
First, update all the video card drivers from each GPU maker's website.
Thank you. I may end up getting another 6970 eventually, I'm not sure. I would hook up all of them to my card but I'm afraid the temperatures will get too high because it's already at 60c idle. (Two 1920x1080 monitors plugged in, 40% fan speed) so I could turn the fan up but I'm very picky when it comes to noise.
For now I will just disable my 3rd monitor, thank you for the help.