I'm over your budget on the power supply and graphics card alone @ 11,441. Question: What is your current power supply's manufacturer and model #? I'm wondering if it supplies enough power to use. You really do need more memory, and the power supply and graphics card already have you over budget.
[strike]Corsair VS450
2,551[/strike]
http://www.amazon.in/dp/B00X8QBT6M
Corsair CX 430
3,520
http://www.amazon.in/dp/B009RMP14M
MSI N750Ti
8,890
http://www.amazon.in/dp/B00I5ZYI5A
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Addendium: My initial response was in error. The Corsair VS model is poor quality, and probably isn't an upgrade from what you currently have. The CX 430 is middle-of-the-line quality, yet still a step up from the VS line. Unfortunately it cost even 1,000. I'd really like you to have the performance of a GTX 750 Ti and a new power supply but I don't see how that's possible with that budget. Therefore, either: (1) we'll have to help you find a lower performing graphics card (2) we'll need to determine if the 750 Ti can run on your current power supply, or (3) you'll need to raise your budget.
Please let me know the manufacture and model # of your existing power supply. Also, please confirm that you have the space in your computer case for a double slot graphics card. You may wish to take a photo of the inside of your case, upload it to imgur and share the link here.
*** power supply tier (quality) list ***
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html