This kind of sounds like you’re asking if they themselves are a new car.
「お前、新しい車があるんですか?」
お前 - you
新しい車 - new car
がある - to have
のですか/んですか - questioning, looking for response
“Do you have a new car?”
Or to better fit the translation,
「お前、新しい車はお前のですか?」
お前 - you, getting listener’s attention
新しい車 - new car
は - sentence marker
お前の - yours (contextually talking about the car)
ですか - questioning
As a quick reminder, お前 can mean “you”, but is both very direct and informal, and is considered to be rude to use in most situations with people you don’t know.
If you want to keep the casual nature of the sentence, but show a bit more respect, you can use the word 「お兄さん」to refer to a young man, or 「お姉さん」to refer to a young woman. Dropping the お makes less respectful, but I think most people would prefer it over 「お前」。
Hope this helps!