The P0113 is a fault in the IAT circuit. Since you've already changed the sensor, I don't think a quick replacement of another part will help. I'm afraid you're down to doing resistance checks as mentioned above. If you don't have a meter, or the knowledge to troubleshoot wiring (please, no offence intended), you'll have to take the car to someone who does...a friend, neighbor, co-worker, or to a shop. Since it worked for a little while, I'd definitely re-visit the sensor first. Double-check the plug too.