Play at 1280x1024 and normally have no problems at full detail, however ArmA arrived today and nobbled my graphics card... it struggles! 
AMD Opteron [email protected]
2GB (2x1GB) GEIL
HIS X1900Pro 600/1300
450w Antec TruPower
The graphics card appears to be the bottleneck and I don't want to change my PSU so a 8800 is out of the question.
So, for a stop gap is the 1950XT worth it and would I notice a considerable difference?
What's the second hand value of my HIS Silent X1900 Pro?

AMD Opteron [email protected]
2GB (2x1GB) GEIL
HIS X1900Pro 600/1300
450w Antec TruPower
The graphics card appears to be the bottleneck and I don't want to change my PSU so a 8800 is out of the question.
So, for a stop gap is the 1950XT worth it and would I notice a considerable difference?
What's the second hand value of my HIS Silent X1900 Pro?