As joshboy said, it's not possible to run 3 screens with your card, you would need 2 of them.
If you did get 2 and wanted to run 3d surround I would go with 1680x1050 screens like the ViewSonic FuHzion VX2268wm or Samsung SyncMaster 2233RZ, with 3 screens side by side I think the 16x10 aspect ratio would be preferable, and they will be a little less demanding than trying to run 3 1080p screens, also cheaper.