Mazda Tribute 2002 ES V6

Was changing out my spark plugs and the bolt snapped that holds down the ignition coil on cylinder #6. I went to hardware store, bought a bolt extractor bit for my drill. Attempted to extract the bolt, but it instead squished the bolt into the brass threads. I now need to replace the brass threading. Thinking that my options (from most desirable to lease) are:
1. Somehow remove the brass threading and replace it?
2. Drill into the bolt and brass, tap a hole, and Helicoli repair kit a new threading into it with different sizing.
3. Replacing the whole valve cover

Any tips would be greatly appreciated

 

Have you figured out a fix yet, or are you still looking for suggestions? I had good luck with Easy Out extractors after the traditional screw extractors proved useless. I was amazed at how easily the screw came out using Easy Outs. They looked like these: