OK, so what you have there is a 450W PSU. I couldn't find exact specs for it, but if it's held its ground for three months it should be fine. However, it's a cheapo PSU. To be absolutely sure you'll need 500W and more, but those cost $50-70 (rs. 3000-4000). It's not that much and if you can spend $60 on this for example:http://www.newegg.com/Product/Product.aspx?Item=N82E16817151093
then you'll be sure you won't have to spend $150 later for a new GPU.