Cars- if you needed a new one or an expensive repair, which would you choose?

My 2001 Toyota is in process of getting a 2nd opinion, but right now it seems I may have threw a rod in my #2 cylinder (in a 4 cyl car), which pretty much takes it out of commission permanently.

Currently I am paying off many medical bills for my husband, so I’m not in a great position for a new car or the payments, but I am turning 40 in January and it has been my plan to reward myself for paying off bills by getting a new car.

So do I replace the engine in my car which otherwise has no problems, buy a new-to-me ‘used’ vehicle, or go for the gold and buy new?

*I should mention my mother has offered me her old truck (1990 Chevy full size) and due to his seizures, I also have my husband’s Dodge Dakota Quad Cab to drive for about 3 more months before a decision must be made.

I’m leaning towards driving my husband’s for now, waiting on the 2nd opinion, then probably purchasing a used car if necessary.