Battery problem with ios 6.1.1

I updated my iphone 4s to 6.1.1. The battery life decreased and the phone heats up.

With ios 6.0, I could get ~7-8 hour usage time and ~24 hour standby time.

With 6.1.1, I can actually see battery going down ~3% every minute.

I can't use my phone. Tell me please what to do.