little piece of the engine head it to break?

Trying to replace the popped timing belt, I broke a part of the engine head. Got it "repaired" by a friend, changed the timing belt, put the engine head back together. and the pressure caused the little piece of the engine head it to break again. In addition before it broke off it was causing a major leakage of oil. Here attached is a picture of what I broke. I live on an island. There is no fabrication shop here that could do something like this as far as I know. Is there any kind of puddy or weld that could fix this?