it is priced about 7600rs so can u suggest some lower ones?
You might want to read this article on best graphics cards for the money:http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107.html
Look at the last page for a heirarchy chart to see how different units compare.
With a 300w psu, you will be restricted to a card that does not need any auxiliary 6 pin psu power leads.
Use this chart for the recommended psu for a variety of graphics cards:http://www.realhardtechx.com/index_archivos/Page362.htm
If your usage is gaming, the stronger the graphics card, the better.
And, if you upgrade, make certain it is a biggish jump of several tiers, or you may be disappointed by a small improvement.