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

The welding trick would be my first choice with that much sticking up. Do you have a friend who welds?
Try heating up with area with your propane torch and using vice grips. After you get the area hot, try rapidly alternating your twisting Clockwise then Counterclockwise. This may help break the bolt loose.
If that doesn't work, I'd try the easy out. In my opinion, one of the most important things to keep in mind when using an easy out is to drill the hole in the bolt AS CLOSE TO EXACTLY THE CENTER AS POSSIBLE! Using some type of a grinding tool, flatten the head of the broken bolt. Then use a punch so the drill bit does not wander. Punch the indentation as close to the center as you can. I always start the hole with a 1/8" bit. I only go down about 1/8" with that bit, then I switch over to the recommended bit size. I feel I can more accurately start the hole with the smaller bit. Then drill down deep enough for the easy out to get a really good grip. Drill in as straight as you can. If that does not work, try this, it has worked well for me many times:
You already have the hole for the easy out. Here is where having a drill bit selection in every 64th of an inch comes in handy. Using the bit size the next size above what you drilled the hole for the easy out, drill straight down into the easy out hole. Use one of the bolts that did not break as a depth guide. Use a few drops of oil to help the bit cut faster and better. Then repeat with the next size bit. Inspect the hole carefully after each drill bit size. Eventually, you will start to see the edges of the threads. At that point, you may very well be able to re-tap the original threads with the appropriate size tap. If the threads are too messed up, you can always use a Heli-Coil and go with the next size larger bolt.