I hate those extractors for small stuff. They almost always break!

At this point I'd buy some 1/8" shank carbide burrs and a use a dremel or small die grinder to remove the middle of the broken extractor/bolt and work until you can pick the thread out of the head. Anything else might cause collateral damage. If the engine was out of the car I might try the welder but with all of that nice blue paint I'd avoid anything like that.

I broke the rear-most passenger side valve cover bolt on one of my charger and had to remove the hood and hood hinge to get a good working angle. It was that or remove the cylinder head.