I might work, but you will definitely be putting a high load on your PSU. The higher the load, the sooner the PSU will fail especially if it is generic (like yours). When a PSU fails it can potentially kill other components in your PC.
Which components? That's the fun part you need to test each and every component. Sometimes it can be none. Sometimes it can be all. Or somewhere in the middle.
umm... Udai, you shouldn't update your card yet, as Jag said, you need to change your PSU in for at least one with 450-500 watts. Any of the 5xxx series recommends a 400 watt but go higher, you never know. Also, your mobo is a bit outdated i must say that even updating the card. You will see performance hold backs. As your mobo only has a 16x/1x PCI express slot. Although 5670 is backwards compatible with the old 1.0 16x slots. You'd still see a drawback. So be sure to get the 16x diamond 5670, or this one. http://www.newegg.com/Product/Product.aspx?Item=N82E168... The reason being this card especially runs on Pci express 16x 1.0 oh btw i don't think there are anymore options for you other than the 1gb card for pci 16x express 1.0.
Sorry for any errors. Hope it helps. It is a bit on the expensive side though just saying.