Auto Insurance....Who carries what?

if i read this right your mother in law lives with you but has her own car and insurance.. if thats the case fax over the moth in laws proff of insurance and tell them to remove the car from your policy being she is the driver and has her own insurance. and the reason it cost more is the safty options on the car the safer the car the cheaper to insure. older cars are less safe thus more to insure.