if your running a 9600 then you have agp, not pci-express. the 9600 is a decent card, but it is somewhat outdated and tries to do some functions through software that is now done with hardware. an upgrade would be a good idea for newer games. I have a computer with a 9800xt in it which is getting old but for its age it will still run fear very respectfully. Problem is after you upgrade the care your gonna wanna start upgrading everything else because your rig won't be able to take full advantage of the video card. haha, its an endless cycle. I would go with the 7600 whether it be the gs or the gt, leadtek is a pretty good brand, in my book they would be pretty equal with evga as i've had good experience with both.
on another note, nearly all newer video cards have two outputs for video, so you'll be fine with nearly everything. good luck to ya.