Your mobo supports pci-e.yes under rs 5000 the best card is hd 6670 ddr3.i reccomend you raise your budget to rs 5600 and get saphhire hd 6670 ddr5.ddr5 is very fast than ddr3.
But will my mobo support hd 6670 ddr5??? cuz motherboard manual says its supports only DDR2 RAMS!!! And are RAMS AND GPU related??? And is it best to stay with Radeon or shall i go looking after Nvidia???
Thanks a lot for spending ur u precious time answering my question!!!!