You should be able to find a 2002-2003 kia between 3-5K $ with lower milage 50-60K . They also come with 10 years powertrain warranty from the manifacturer.
Given your credit situation, which is very similar to mine, would be very hard to get fininced with 0 money down for the following reasons:
1- If you purchase a used car, the bank will finance at the most the whosale price. Most dealer sell cars well over whosale, plus you will have to add tax and licence cost.
2- Most of the secondary financing company will charge the dealer a bank fee as much as 30% x each 1000 $ you finance. So if you lucky to find a dealer that is willing to sell you a low milage car for whosale, you will still have to come up with the bank fees.
3 - The interest rate you got at 19% with 3000$ down appears to be very good for your credit score based on my experince (no credit expert by any mean, but sold/puchased many cars).
4- Most of the dealer that I dealt with that provide in house finincing will require 30-50% down and charge between 21-29% interest rate.
Your best bet is to find a side-lot. Buy a 2002 or newer Kia/Hunday/Ford with low milage at whosale price. Check Kelly Blue Book and N.A.D.A trade in value. You should offer very close to that. Note: Most dealer won't accept that low of an offer but it will happen if you do not give up. Done many times..
One more thing. Try not to run your credit a lot, it will lower your score an chances to get a loan (too many inquires). Best option get a copy of your credit report and take it to the dealer so the can see what your credit looks like.
Good luck,.