Need a new card

Hi all, I built a computer 5 years ago or something and it's been running fine until yesterday. My GPU kind of died or something and now I can't use it. I have around 200 dollars to spend and was wondering which card would be good for my money and for my system.

I haven't built a computer in years (too busy, this one is fine for the games I play (TF2, ME2, DA , etc)) so I kind of got no idea of what;s compatbile and what's good.

I have an Asus P5B mother board with 3gb ram on a Windows XP system, E6600 dual core cpu, my old gpu was an EVGA Geforce 7950 GTX, my cooling is pretty rudimentary with one fan in the front, one in the side and one in the back, the system has always run hotter than I wanted with cpu constatnly at 50 degrees celsius (even with new fan).

I currently use some generic power supply (cost me around 30 dollars) which supposedly is 550w, has worked all these years with no problems whatsoever.