^^ Its VX450- and the cost is 3.9k. Prices have increased since 2-3 months now.
iBall will surely destroy the system with 4850. its obvious that its a sub standard power supply. Ati 4850 takes 110w on max load so you will need to connect the 6 pin pcie connector. Its obvious in this day of age that you need to have a proper supply, takes lesser wattage from the socket and solves more than half of the problem on the pc. As I say in many forums, if you cant afford a decent enough power supply, dont bother buying a decent enough system. If you really want to know how to choose a proper power supply, here's the guide:
*thinkdigit.com/forum/showthread.php?p=1017224#post1017224