iphone 5 keep restarting after ios 7.0.3 update

Hello,

I just updated my iphone 5 to ios 7.0.3 two hours ago and it have been restarting itself (every five minutes or so) ever since. I've tried restarting, resetting all network, erase all data, restore, and a hard restore. I can't back up my data because the phone shuts off before the backup complete (computer and icloud). I'm afraid if I take it to the apple store, they might not be able to help me because I fear that this issue is not fixable at a store level. My warranty already expired so that leave me no other choice.

I figure my only solution (if someone at the apple store can't fix) is either pay to get a new one or wait until ios 7.0.4 or 7.1 roll out (if i'm able to install it in time).

Does anybody else have this issue and know of a good solution?