XPS700 Video card upgrade

Good morning folks
I am looking for a video card upgrade for my  now ageing xps 700 and was wondering if the people in the community can help. As my warranty is  gone and i am having a little trouble with my front panel switch i am looking to buy a new card for my beastie. The current config is 4gb ram, 512mb PCIe x16 ATI Radeon X1900 XTX , XP Pro,creative sound card etc. As this machine is used mainly for  - photoshop -  graphics and gaming, just finished call of duty modern warfare 2 - again ! i can afford to spend a bit on the gpu but im not into overclocking as it has to work reliably first time for the applications i use. This is the cheaper option then getting a new system at the moment though that would have to be considered  later Your thoughts on this subject appreciated :emotion-1:

Thanks UKW