Resetting Network Settings?

It resets the network settings to what you had when you got the phone.

Anyway, that's the last thing I'd do, since it shouldn't help with your battery. Mainly, you need to go through a number of charge/discharge cycles before thinking the battery is actually that bad. Also, you may be using it more than is normal, since you just got it. If it still bothers you, go back to the store.