Prop repair shops work mainly with aluminum, repairing props, skegs, and cavitation plates. A close prop shop for you would be the one Gregg suggested, Propulsion Props in Hudson, WI.
http://www.propfix.com/store/home.phpMarks Prop Shop in Stacy, MN repairs props and specializes in welding aluminum. Mark has worked on my bronze props, but he works alot with aluminum on props and for the medical industry.
http://www.markspropshop.com/Either would do good work. Get the holes filled in the cavitation plate from the fins while you are at it.
And get the side of your boat fixed from the ATV accident in your garage this spring. LOL