1999 Pontiac Grand Am V6 crankshaft

I have a 1999 Grand Am 3.2 engine 140,000 miles. I drove the car home (It was driving perfect) came out the next morning after a cold night and the car would not do anything. It was completly dead. I had my grand am towed to a local repair shop. The mechanic informed me that the cam shaft had broken and there are metal flakes in the oil. He said I would need a new engine. Due to the cost of the repairs I had it towed home and it has been sitting for the last year. I recently had the car towed to a different repair shop to have the engine rebuilt which would cost $2000. Upon looking at the engine this mechanic says that it is the crank shaft that broke and if I had the engine rebuilt I would just continue to have problems. He suggested getting a engine from a salvage yard and having it put in. Can the crank shaft be repaired? I am a young mother of 3 and don't know if it is worth $1500 to have a salvaged motor put in that has 80,000 miles on it already. Or if I should just get a different car. Thank you for your help!