Unfortunately it doesn't really work that way. You bought it, it's yours. The only way you might possibly be able to get a refund is if you get the police involved, but to be honest,t he guy did nothing wrong. The people who did something wrong was you and your Dad, for not bothering to get the car checked out first by a professional (which you could have requested from the previous owner) before handing over your money.
Pretty much, you and your family should live and learn, and research the process of buying a car so that next time you don't get screwed over.
Pretty much, you and your family should live and learn, and research the process of buying a car so that next time you don't get screwed over.