Crysis 3 will be pushing the limits, but as long as you are on low res then a 7770 is a great choice. AMD is very underestimated in the graphics world and most of there cards come at great prices. Nix327's suggestions are spot on
The 7770 gives decent fps for most games at 1920*1080 at low to medium settings..so i believe it can do much more than low settings at 1366*768. the 7770ghz edition performs better and the ones i suggested can also be oveclocked..here is a benchmark for the 7770.
In india parts cost more than they do in US..200$ is like Rs 10,000..and a 7770ghz edition is already pushing your budget..its better for you to get a normal 7770 and a corsair cx 430..parts are cheaper when you get them from retail stores..
Correct me if i am wrong, but I think there is not much of a performance difference b/w GHz edition or normal 7770 ? In that case i will go for the normal 7770. If a 7750 works for Crysis 3 may be i will then go for that to stay in budget as i am going to play the same in 1366x768.
One more question, i3-3220, Gigabyte H77M-D3H, Gigabyte 7770, RAM 4GBx1 - this combination will be supported by a 450W PSU ?
From ur suggestions I can see the importance of a good PSU. Let me check with the retailer if he will replace the current PSU (it came with the intex - mini ATX- cabinet).