even I'm surprised to see a GTX 570 selling at such low price but few days ago when I checked flipkart the card did not show up among lowest to highest priced gfx cards - this is just an error and the gfx card is out of stock right now.
@ OP - if you have suitable cpu and ~22k budget opt for HD7870 or if you have ~3k budget either get GT520 or GT240.