Since it sounds like the motor threw a rod out the side of your block,
which is probably
NOT timing belt related,
but,
could be related to the re-man that was performed (incorrect torque on the rods or mains, forgetting to tighten the oil pump pick up tube, or any number of other reasons)
I would suggest a gently used motor.
I like this website
Car-Part.com--Used Auto Parts Market
They have thousands of bone yards on the list and you can find one near your house or get something shipped to you from Mexico, or Canada, or South Carolina.
Engine swap on a Metro is fairly easy and straight forward.
You don't really need a hoist if you don't have one.
just be sure all the other fluids are drained first.
and remove all the pulleys on the front of the motor to give you room to pass the clutch.
I am in the process of thrashing mine right now.
keep us posted,
Schultz