Look on sites like Craigs List, etc. People might be selling the old mixers for parts or the parts themselves. Yard/garage sales are also good places to go as well as second hand stores, etc.
You will not be finding a new piece for it for sure. First it is an obsolete model, and second, the company that made it doesn't make them any more and the company that took over won't be stocking old parts that don't belong to "their" machines.
Good luck. I love my KA and while mine is only 5 years old, I know they can last forever.