The big bit is you had USED parts on it when she was hit. You will not win the new OEM part fight but you will if you insist on a minimum of OEM used. I would go that route and avoid aftermarket if you can.The car had OEM parts on it when she was hit so they should replace it as it was before the accident. I’d get a lawyer and let him work it out. Your wife probably has “unknown” injuries which won’t show up for awhile. She needs to see a doctor. I speak from personal experience.
You will not win this fight if your car is more than a year old. Save your energy and focus on used parts.