I wait for the day that my 8800GTX acs3 card wont run a new game. I love to see technology improve but it hurts to know a video card you paid hundreds of dollars for can no longer meet minimum specs.
You will want to consider sometime in the near future building a new system with a pci-express slot to take advantage of the new cards out now. If its over only 1 game, you can put it off a while but the time is running out for your current system. You have gotten your moneys worth from that system. =D