https://en.wikipedia.org/wiki/Volvo_Redblock_Engine
" All single camshaft versions of the engine with the exception of the K series (B200K, B230K) are of 'non-interference' design, meaning that failure of the toothed belt will not result in engine damage."
If you decide to tackle the cambelt change yourself, the money saved could be put to having someone doing the metal repair.
Or, you could get hold of a cheapish mig welder and have a go yourself.
I might add, that once the timing marks are lined up it's unlikely the camshaft will move (out of alignment) by itself.
Best of luck, whatever course of action you take.