Hmm... the game certainly should run on high quality with those specs. I think the problem is that the card is too new. The game tries to autodetect what settings your card can handle, but it doesn't seem to be doing a very good job!
I think replacing the prefs.prop file in your CSI3 game folder will do the trick. Just overwrite the one that's in there with the one attached here. (Unzip it first!)
Please let us know if this fixes it.