Set Position and Rotation with another GameObject as Pivot (Script)

Hi, I have a problem with moving the car with my character inside, i want that the character follow position and rotation of the car (seat), but i can't bind that with my character directly bacause the pivot is the feet, so i created a Gameobject as reference point... but how i can move my character with that reference?

so, the blue cirlce of the character must be at the blue circe of the car, but "carrying" the character. Thanks in advance!