I have a car that I painted 6 years ago myself with a Dupont base coat clear coat system. I was hit on the driver's side front fender and I am going to have to knock out a big dent and repair about an 18 inch square area. I have the paint mumbers from the original paint that I used, but I know this will not match my 6 year old paint job. My question is how do I get the new paint that I am going to purchase, to match my old paint, so I don't have to paint the whole car??