if you cook yourself by organizing everything from A to Z, in a very standard level. food expense monthly will be 2000/-
If you go and eat outside in a standard hotel, then your 4500/- is correct fit figure for one month. and all other expences i dont know about it.
In 3rd class life style schedule:- option 2

Indian food self coocking monthly 1000/-
Indian restaurent food monthly 1500/- one buffet only.

so, you tell me what is your stomach stle? then i can give you precised calculation that suit to your budget.
Good luck.