I think you should find out why that cracked before even thinking of repairing it. That is a very odd crack.
Well, that area isn't of particular stress I don't think. You might be able to just weld it back up. As long as its oil tight I don't see a problem.
You can get a rebuilt one on ebay and send them this one as the core though for $350. It says they'll take any core. I'd be weary personally of that head in my car.
Any picks or explaination of the tool or how the hail you came to this end? Its very weldable, with the right person doing the work. Any warpage is a no go. Leave the cam in and put the valve cover back on to hold everything in place the bast you can. Tac the outside nice and slow in several places. Then move to the inside, tac what you can then remove the cam. There are products made to absorb heat that can be used as well as gas baths to help as well. Best case, buy a new head. Im sure it couldnt hurt anyway.
Do not use brake clean to clean the parts before welding as this could cause death.