Abinav :
i dont know any details about graphic cards so plz help me
well, to answer that, here's a few questions.
1. what is your power supply rated at?
2. what model motherboard do you have?
3. Are you going to replace the cpu? this is very important, as that cpu is far to weak to drive anything remotely powerful.
4. what do you need the graphics card for? browsing, gaming, ece?