I use a car perfume from an Italian skin care company called L'Erbolario. It is actually smells much better than the general stuff you for cars. I've had my car about the same length of time as you and people still tell me it smells like a new car
Here's the website http://www.primexint.com.au/08products/home/car.shtml
I use the mayflower scent in the car which (and I have no idea why) people associate it with a new car smell.