Broke my water pump bolt. Now what? (Update - broken bolt is out)

The I would do it without a welder is to heat the block around the bolt (not the bolt) with a torch and when it is good and hot then spray with penetrating oil may take several tries. Then hit it with a hammer to vibrate the bolt and keep spraying with penetrating oil rinse and repeat. It would be best if you could get someone with a welder to weld a nut on it and then doe the other steps.