Bad Battery Life iPhone 5 iOS 6.1

This is just unacceptable.My iPhone 5 wasn't very good with the battery on ios 6.0.1 but now on 6.1 it is absolutely unacceptable.I charge it overnight to 100% ,I go to my university at 8 and it's down to 64% by just 11 am.This is just a 2-3 hours of usage,most of it being standy.I DO NOT use LTE or Cellular Data.

I've restored the phone ,set up as a new phone but that doesn't seem to work.I tried turning of Cellular date and putting the phone in airplane mode for an entire day but that doesn't seem to stop the drain either.I heard about the exchange bug ,but then I do not exchange.Only Gmail.Unfortunately ,I purchased the phone from the US and I am right now in Pakistan so I can't take it to an Apple store.I do feel this is a software issue.I don't know what to do ,I should just sell this phone and buy a Nexus 4 for less than half the price (700 dollars) that I paid for this unlocked iPhone 5.