The whole car buying process takes 3 to 4 hours of negotiating back and forth once you find the car you want to purchase. Do a lot of research on the vehicle by looking at "Carsdirect.com" because they tell you what the average dealer pays for the car so you know what the mark up is on the particular car you want. Ask to see the Invoice on the car you want to buy and start your negotiating at that #, NEVER start with the MSRP or DealerInvoice (dealerinvoice being MSRP + some kind of dealer mark up)
I would suggest giving the $4k as a down payment. Having cash money down will help you get a lower interest rate.
Use the dealership for financing because you will get a better rate with longer terms then using any other service (CU or Cap1)
Negotiate Price, then Negotiate Interest Rate and Terms....don't let the dealer try to sell you on a monthly payment b/c they will get you with that trick.
I've bought 3 new cars in the last 3 years.......