Card to replace ATI 5850

[Whytey]

My 5850 has gone faulty i'm looking for a cheap replacement. As of now I only use my system for designing, video editing and watching HD content. Since my Card is out of warranty, I don't want to spend that much on a card
[max probably around £100]

Also is it worth getting more RAM if i want to increase the speed of running more applications at once?

SPECS
Gigabyte H55M-UD2H
Intel i3
Corsair XMS3 2x4GBS
Corsair TX 650
24" ASUS IPS Panel + 18" LCD
Windows 7

 

[PapaLazaru]

How much money have you got to play with?

 

[Whytey]

I'm not really into spending more than £100