iPhone 3GS unresponsive after updating to iOS 6.1.3

My unlocked iPhone 3GS's touch screen and volume buttons has become unresponsive after allowing iTunes 11.0.2 to update the iPhone to iOS 6.1.3. I have tried restarting, resetting and restoring the iPhone several times. It will no longer function at all without a SIM so I purchased an "Amaysim" prepaid SIM so I could use the phone however this has not acheived anytihng.

My phone is now a brick - any help would be greatly appreciated.