Installing graphics card - where to plug in?

I just picked up the Apple LED display with camera, etc, as well as a new 4870 card to use it on my early 2009 Mac Pro with. I went to install it and ran into a bit of an issue. There is already one graphics card installed, two Superdrives, and 4 hard drives. The 4870 requires both power slots on the board, meaning I'd have to unplug my current graphics card to power it. This would be ok, except I'm now running three displays and need both cards. Where's the best place to pull power from in a case like this?