LGA 775? Yes you can have more power by using a QX9650, or Q9650, especially if your MB allows you to overclock. You would also need to run a later gen GPU, like the 680 or one of the Ati cards. I would also, certainly, jump to 4GB, or as much as 8GB of RAM.
Now, consider how much that would cost you and compare that to what new would run and base your decision on the age of what you would have to carry forward (MB, PSU, etc.) and having to upgrade within three years anyway. Probably it's time to change the GPU either way, so consider that also.