Mitsubishi Outlander 2011: Rust specks on new car?

When I picked up my new car in March I thought everything was fantastic until my husband gave it a close inspection. The car, all shiny and white, was covered in tiny rust coloured specks. He washed it the next day, but the marks wouldn't wash off. I returned it to the dealer expecting the marks to be removed, but unfortunately they weren't. My lovely white Outlander is now covered in scratches and the black trims around the doors and the black roof bars are also scratched. When we phoned the dealer to complain they asked us to return the car for another attempt to polish out the scratches and rub marks. Unfortunately, although there is some improvement, the car still looks like a poorly maintained used car rather than a brand new car with less than a 1000 km on the clock. Am I within my rights to ask for a replacement vehicle? How long do I have to keep taking the vehicle back for them to keep trying to fix the mess? If this was a TV or a fridge I would just take it back and have it replaced, am I not entitled to have what I paid a large amount of money for, a NEW car? This has certainly has taken the shine off buying a new car.