What Should I do with my Iphone 5?

I have a iPhone. It was stolen from me and i got it back. The people who bought the stolen phone did not, know how to, use it so they tried to open the back cover thinkn, its a, normal phone and its full of cracks and all… Wen i gave it to imagine store they said yu, need to pay 26 thousand bucks to replace it. And 10 thousand to upgrade it. What shud i do? I can afford it but i'm nly 14 so i really don't care havn an old phone. But wud Yu recommend gettn a new phone?

Is it working? If it is, just buy iPhone case that will cover back and sides, like this:

http://www.amazon.com/...00D94RCV4/