First, take an appropriate tap and clean out every other threaded hole in the block that are not yet used.

As to the busted bolt and extractor, my suggestion is to retain the services of a skilled machinist to remedy the situation. That will likely be the cheapest money going.

An old parable comes into play here... "If you find that you are digging yourself into a hole, stop digging". I have been in the same fix and I just muddled on and really made a mess of it. That is a most common outcome.

Save yourself the frustration (an money)!

Not to be mean spirited, but first you broke the bolt off (you really shouldn't have done that), then you broke the extractor (really easy to do, OBTW).
Things are not running your way at this point. Your inexperience shows and just watching a pro do the task would be a valuable training session. There are a few key points that you can avail yourself to.

Best of luck

mike
--
64 220 (RIP, now he's parts on the hoof) - 65 220 - 68 220 (almost ready for the road), and a 66 130 (35k miles last year)