Why don't you just take the title to the local MVD office and have it put in your name? Otherwise, talk to the impounding authority about what they need to prove ownership. Purchase papers, possession of the title document, prove of payment of the purchase price, proof of insurance, affidavits etc.
The above "answer" is for discussion purposes only and is neither intended as legal advice nor to create an attorney-client relationship. An attorney-client relationship is not created until after an in person consultation and I agree in writing to provide representation. I am licensed solely in the state of Arizona. You should consult with a knowledgeable attorney in your jurisdiction.