I don't think a heli coil will work too well for that... the diameter of the hole appears to be too big for a heli coil to resize it to the proper size.
But don't worry... the fix is actually pretty easy, I had to do the same thing myself when my stud broke as well.
That hole is drilled to a certain diameter, you will need to find out what that size is. Then go to your local hardware store and go to the racks where they have steel bars, rods, and sheet metal. Get a piece of threaded bar/rod that is the proper size.
Then you will have to tap the head to the same thread pitch as that bar so you can thread it in.
Next, take the bar and thread it in as far as it will go until it bottoms out. Now mark it off to where it would be flush with the head so you can cut it to the proper length.
Cut it to that length. Now before you thread it back in, drill and tap a hole in the center of it that is the original size and thread.
You will want a shorty bolt (shorter than the plug), take it and thread it into the small hole so that way you have a way to put a wrench on it and tighten the plug into the head. Remember to put some red lock tite on the plug so that way it is stuck in there and wont come out.
After its in and snugged up, take the shorty bolt out of the plug and viola! you have the head back ready to use.
This is a bit of a pain in the ass and time consuming to be honest, but it works and lasts. I've flogged my warrior for about 2 years now since I fixed it this way and there have been no issues. Just take your time and it will be fine.
