Correct Journal Entry for using biz funds for Car Purchase down payment?

I used business funds for the down payment of my new car but all monthly payments are being paid with my personal account.  I do claim mileage in my business but nothing else (fuel, maitenance, etc).  How should I enter/set up the cash used for the down payment? I don't know if I should be setting up a fixed asset or applying it to an owner disbursement or?  Thanks for any assistance!