Hi and thank you for question, my name is ***** ***** I will be happy to assist you.
There is one thing you can try and thats updating the Magellan device. To perform the update, follow these instructions by clicking here.
If that doesnt fix it that I am afraid you are out of luck. There is no calibration procedure for the touchscreen on these units and your only option will be to send it in for repair. Your device is out of warranty, each warranty comes with a one year warranty and most likely the repair will cost more than the purchase of a new unit.