You can fix that yourself. Solder is ok but very soft. Id solder a small piece of copper into the hole and then file the shape. Probably a 18th inch piece of 12 or 14 guage solid wire.

Look closely and you can probably take the arm off easily and then get the wiper to the bench for access.

I've used a company called Sending Unit Repair and Rebuild. Results are hit and miss.