changing out my 6 speed to an auto?

OKC Z

The reason im wanting the change is because my mother was in an collision where they destroyed her Solara. Shes been going thru some stuff as it is and now she wont be able to get another car. She likes my car but she has never been able to drive cars with MT and now at 50+ yrs its harder and specially in a Z. Im gonna shop around for a wrecked Z to see if its cheaper to buy parts or take a hit and trade it in for something else. The car is right at trade in value so everything Ive payed in will be lost, like if I leased it. I was thinking something around 3-4k in parts, am i way off?