Workstation gfx card for £2-300

I need a workstation gfx card for use with Maya, other 3D apps and Photoshop too. Budget is GBP 300 max, but from what I can see there is a big price gap between the FX580 @ £150 and the FX1800 @ £400.

Are there other options? I've read Nvidia cards are better in Maya than Ati cards but I've hardly scratched the surface

Also, my CPU is an old dual-core 820 D @ 2.8ghz, is it worth getting the more expensive card or will my cpu cause a bottleneck. Overclocking is a nogo btw