a GTX 295 is still very powerful even by todays standards so in order for you to even get an upgrade, you must buy a very high end card.
A GTX 570 or AMD 6970 would be somewhat of an upgrade in terms of a tad better performance and way superior thermal performance. But in order for a significant upgrade; you'll either need to buy a gtx 580 and OC the crap out of it or you need to invest in SLI solutions such as 2x GTX 560TI or crossfire 2x HD6950's.
or you can upgrade to dual gpu hd6990 or gtx 590...
Geforce 295 is still a very reasonable graphic card, which should be able to run FSX/rfactor etc. without any problem. I would suggest that you should keep both your CPU and graphic card for now, and build a new system a year or so down the road.