Trying to get the last out of my SN25P

[sjhujh]

I'm just trying to get the last bit of use out of my SN25P before I eventually upgrade to the P2 series (or what ever is current when I rebuild)

My Spec is 4200+ x2, 1 GB Corsair TwinX ram, X800XL. I recently replaced my old 3000+ single core for the X2 and now i'm turning my attention to the GFX card. Currently i'm thinking of getting a X1950pro, as these seem to be in the sub £100 price range.

Just hoping to get some feedback from you guys about if you think its a good idea? I haven't really been keeping up to date with hardware after my intial build as I kind of buried my head in the sand, otherwise I proberbly would have been upgrading every few months! I'm hoping to keep the system going untill well into 2008, maybe begining of 09 when I will have saved the money needed to build a new gaming rig.

My main questions are will the X1950pro let me do this? Will the shuttle take it? Will the PSU be able to handle it? (the other components are 4200+ X2 toledo core, Seagate 200gb drive and Samsung 400Gb drive and 1gb Corsair ram everything is running at stock speeds).

Also i've seen some 7900GS's knocking round for about 80 quid is this a better option than the ATI card?

Only just put the new CPU in so haven't tinkered with the clock speeds.

Thanks