You can get you a new timing cover from EB for 50-ish bucks.
I'd order it now and you can install it as they finish up your head. You can get a new timing kit too from EB, with the steel guides, rather than plastic.
Is all of the plastic guide that broke, all there? If pieces are missing, then they worked their way down to the oil pan. IF this is the case, you'll wanna remove your oil pan to get those pieces outta there. Those pieces will block the oil flow at the sump screen, and stop oil flow in the engine. Trust me, I bought a used engine with a "rattle" problem. Wasn't a rattle, is was a knock - bad knock. Ended up rebuilding the entire engine, because plastic guide pieces were blocking all oil flow.