How to remove a crank arm with stripped threads?
Your crank arm is trashed. 

With the crank bolt removed, gently ride around a few miles, it should work itself loose enough that you can yank it off.

Otherwise many shops have basically a slightly larger crank puller for addressing this issue, where they chase out a larger set of threads, then use the larger puller to get it off. The crank arm typically goes into the garbage at that point however.