All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The money you have stolen from your father is a debt which you are obliged to pay back to him and your repentance will not be complete until you ask your father to pardon you or until you give him back the money. For more benefit, please refer to Fataawa 85498 and 86527.
You can return the money to your father from any money that you obtain in a lawful way, so if your father gives you some money and then you give it back to him in place of the money which you have stolen from him, it would be sufficient and acceptable.
As regards the items which you have bought with that money, it is permissible for you to benefit from them and their value is a debt which you are obliged to give back to your father.
Allaah Knows best.