You're not far off. The first issue I see is that your car struct is using arrays for cap, doors, costp, and sellp. Those fields are just numbers in your file, so they can just be ints. Here is the modified car structure:
You had the right idea for reading in the data -- you can simply use >> on an input stream. You don't need to use endl at the end either. Here's a program that reads all the data in:
struct car car;
fin >> car.rego >> car.make >> car.model >> car.colour >> car.cap >> car.doors >> car.costp >> car.sellp;
Scott J. Kleper
Author, "Professional C++"