Broken bolt in head

When I was stripping the engine I broke one of the bolts that secures the heater take off to the head. I drilled and re-tapped the thread. I have now broken the tapping screw off inside the bolt hole. So now I need to extract this broken peice of hardened steal.

Is there any way I can remove this without widening the hole. Or is there anyone with the know how and patience that I am so desperately lacking that could maybe lend me a hand.

Nothing has gone too well today mini wise.

James