Iphone 4 without itunes or lock button
You have a few options:
Option #1

Take it to the Apple store and have them fix the lock button.
Take your iPhone back home, and run iTunes on a friend's computer.

Option #2

Take it to the Apple store and have them do everything for you.

Option #3

Go to the Apple store and get your lock button fixed.
Get a real computer that supports iTunes in some way or another and use that.

Option #4

Go to the Apple store and get a real iPhone - one that actually supports modern software.

In reality, you've got no good options.  You need to go to the Apple store one way or another.  Sorry bro, welcome to 2016.