they are available for less than $15 shipped off ebay.

i know this seems to be a common problem with the extreme temps, so i would probably inspect where the crack occurred and fill /reinforce that area with an epoxy.

Did you already pay to have it fixed? Its not an EASY first DIY repair, but if you can figure out how to do spark plugs or something similar you will figure out this pretty quick, and only the first one will seem hard.