Can you buy something like Soft Paws to cover the cat's claws? I don't know where you live, but we have access to little nail covers you glue over a cat's claws. They are soft covers and completely prevent damage to furniture.
SoftPaws.com - Nail Caps for Cats and Dogs
Or can you, you know, TRIM her claws? If she is full indoors, there is no reason her claws can't be trimmed/clipped, both front and back. Even if you don't have access to something like Soft Paws, surely you can buy cat claw-clippers.
Scratching is something cats do as an instinct and you can't "train" it out of them, so you need to work around it. I understand parents being upset, but shoving your cat outdoors would be as cruel as throwing a toddler outside. Your cat has not been an outdoors cat and has NO idea how to deal with things. She is going to be terrified of everything.
EVERYTHING is a danger to your cat outdoors right now. Other animals, other people, insects, parasites, diseases, weather. She might get spooked by another animal and run into the road - cats can't "reason" and remember "not" to run into the road if they're terrified and fleeing something else.
And by "infertile", do you mean spayed? Is she vaccinated, at least?