very few remaining 9500s (if any) can still be turned into 9700 np's. You would need to get one that has the memory in an L-shape around the GPU, but don't be fooled by screenshots given at the store's web site (i.e. ask them to make sure that the ones they carry actually have their memory configured that way). My advice, don't waste your time looking for one, cause ATI pulled the plug on that pretty quick. Get yourself a 9500 Pro if you can still find one, or if you've got a hankerin' for some overclocking, a 9600 Pro. Those are both excellent cards.
Edit: The new 5600 Ultra's are very decent also