This has been tickling the back of my brain. I read this story years ago. The MC is driving back home and ends up buying two teenage girls (younger sister later revealed to be psychic) that have had a really hard life (abuse and neglect). He takes them in and marries/adopts them. I remember he buys the older sister an Alfa Romeo Spyder.
I seem to remember it was by Rod O'Steele and called "I Bought Two Girls" but I can't find any evidence it ever existed.
TIA for anyone that can help.