Go for sapphire 2gb 7850 or gigabyte 7870 2gb if that is within your budget .
http://www.flipkart.com/sapphire-hd-7870-xt-boost-2-gb-gddr5-graphics-card/p/itmdhwhubdaf5ds3?pid=GRCDHWHZ4QZRHWYX&ref=ca5347eb-fa78-4a16-92f7-afbabc51c5fc&srno=m_1_4&otracker=from-search&query=7870
This one is great...