damn! sorry to hear that!
there are a few different types. depending on where you tore it they can just sew it down. thats the safest option and the least intrusive. its literally a 25 min operation. alternatively you can just leave it and let it heal itself, although you'll never be able to race skier cross as hard again.
the other option which you mentioned is a replacement of the acl with a hamstring tendon. i think they can use other ones too but i dont know enough about it. i do know that it involves drilling through the anterior face of the tibia upwards through the top of the bone, then the same downwards through the femur, creating a channel for the new tendon to grip. google images of it, its really amazing.
despite what most people say its not the most traumatic knee operation you can have. my patellar realignment in november was far worse. longer recovery, more muscle wastage and significantly more invasive surgery.