No brainer - Take it to the apple store - trust me. They will also give you a report on the rest of the phone i.e. is the screen a joey, are the speakers OK.
Unless you know a local store that are good (references etc - they still use non apple stock btw).
We have a store in a local market that are good but they are only £20 cheaper than the apple store price. We have one also that charges £10 more than apple for the same job - I still went to apple.
B