Replacing Graphics Card - Replacement Options
I have a Late 2009 iMac - i7 2.8 with an ATI Radeon HD 4850 w/512MB. I'm trying to extend the life on this iMac. I am been having some graphics issues and would like to replace the card. My question is what card options are there for this (new or used) - if possible I would like to at least step up to a 1 GB card.
Can anyone recommend a suitable graphics upgrade - or, at least a replacement for this? If you have links, even better!