No worries. Forgot to mention a GTX 550Ti would also be a viable upgrade for you (though it is slower than a gtx 460). I would guess that any card you buy now you likely will not have a use for in a couple years if you upgrade. Not many people bother with dedicated physx cards anymore. Once you upgrade your graphics card you will notice that you are going to become CPU limited in many games...so overclocking the CPU would help out (I have an amd phenom II x3 710, which should be similar to your processor, and a gtx 460 and it runs great, but my CPU runs out of processing power more often than the graphics card). That said if you are happy with your current gaming performance, you would be fine. Here are a couple charts for your info....one of them has a 9800gt in it.
