Alternator bolt threads stripped in the head

Thought I would work on my son's 67 notchback today and put the alternator on since I had an hour or so to play with it. Realized quickly the threads in cylinder head are stripped. Even worse, there appears to be the remains of a bolt in the hole. I rig up a sleeve to fit around the drill bit that fits inside the hole to keep it centered and start drilling. That's when I find out that what I am trying to drill is hard as hell. I am wondering if it is a broken off easy out.

Crap! I guess I will go get a brand new cobalt drill bit. This could take a while. So much for an easy job....