Could RMA it if the warranty is still good, but I'll give some cards.
Assuming you are using the non-G92 chipset the upgrade options can be:
- 9800 GTX
- AMD HD3870 X2
- 8800GTX (expensive)
- 8800 GTS 512MB with the G92 chipset.
- 8800 GT 512MB
Though the best price/performance is probably the 8800GT.