i don't know if this is constructive advice, but it's an interference engine, so if the belt broke while the engine was running there was likely piston to valve contact. this can bend and break things, so i bet it's an expensive repair (on the order of the cost of an old Subaru). of course, this is my own speculation...
as i understand, the only safe way to remove the timing belt is to put the crank (and valve) rotation into a special 'service' position that prevents contact.
even if the engine was only idling, collision between the valves and pistons can bend or break things.
in order to diagnose things from here, you'd need a mechanism to look into the head at the valves.. or you'd need to replace the timing belt and perform a compression test.
a usb borescope can be bought online for ~$20 or so. with that you could look into the intake or exhaust port or through the spark plug hole and inspect the valves and piston.
i think that a timing belt kit costs $200-$300, but i don't know how to go about installing one on an engine that had the belt removed while not in the service position. maybe there's a way to rotate the crankshaft so that the pistons withdraw from top dead center. if the timing belt were to be installed incorrectly, then there could be more damage as the engine is rotated during the compression test, though.