Car Loan with Bad Fico score

I have to purchase a vehicle. I just check my Fico score its a 596. I have paid for the vehicle loan that was in my mother's name (the vehicle I currently own) but in her name. How can I show this to the dealership finance that I was the one responsible for paying the car note from 2001 to 2010 (remember this account is in my mothers name but I paid the loan)?