Small Upgrades to Old Rig

I want to Upgrade this rig to play games at medium settings
Budget-Maximum 28,000
Rig-
Intel Pentium Dual Core E5200
2 GB Transcend RAM
Gigabyte GA-G31M-E2SL
Want to add GPU and Want to change Processor Also
Suggest a PSU according to need.... i think Corsair CX430V2 will Suffice
Is C2D E7500 will be good choice
I have following plans-
Inel C2D E7500 - 6k
2GB DDR2 RAM - 1.4k
Corsair CX430V2 - 2.5k
Sapphire HD 7850 2 GB - 14.6k
Cooler Master K380 - 3.2k