i currently have a mercury motherboard 845GL . my system vendor says that i cannot add a grapfics card to it . if its true i need to buy a new motherboard which goes quite well on performance and supports a graphics card . could u please tell me what kind of motherboard i can buy and also what graphics card i can buy. my estimate for motherboard is max 4500 Rs. and for graphics card is from 4000-7000 rs.