You will need an aftermarket cooler to overclock AMD FX 6300 to 4.5 ghz I'd suggest
-Coolermaster Hyper 212 evo Rs 2500 (around)
that will give you an extra 10-15 fps while gaming...!!
For the Graphics card,....Buy the hd 7850 OC edition 2gb gddr5 Rs 17300
because it has more overclocking (upto 1400mhz ) than the gtx 660..