Thanks for the responses so far.first, why do you want to upgrade, you never really stated a reason other than playing games, your pc will play modern games in low res with low textures just fine.
I had a Radeon HD 4850 for some time and the on board fan died and I started getting crashes caused by crazy high gpu temps (talking 212F). I'd been toying with the idea of upgrading for sometime and all those crashes really pushed upgrading to the forefront. I'm usually one to spend a great deal of time researching stuff before I buy it but the other day I said "fuck it", went to Best Buy and bought the GeForce GT 740 and 4 additional gigs of ram (like $180 total). It certainly fixed my issue but now I'm toying with the idea of not just scraping by on game performance. I mainly play Planetside 2 these days, if that helps.