I'm 20 and I can't even afford lessons let alone manage to run a car! I'm at University, I'm up to my eyeballs in debt and I'm not even qualified yet!!! By the end of my degree I will owe £21,000 and thats not including the interest (which was supposed to be around 2% but they have since decided to double it!!!) Sorry, University fees are a bit of a sore point. Hopefully I can get a summer job and then I can actually learn to drive.
Anyway, this probably isn't very helpful but speaking as someone who doesn't have a car I'd be happy with anything, so maybe you just need to change the way you are thinking about it. Maybe instead of looking at peers with expensive cars look at those of us who have to walk. You just have to try to see the bright side sometimes, at least walking gives me plenty of exercise.
Alternatively, a bit of decoration inside might make you feel more at home in it and you could just mention to your parents that you would feel happier with something else, its not that you don't appreciate it but you just don't feel as happy driving it as you did your old one. At least give them the opportunity to say no, they might surprise you if you present a good argument.
Otherwise get a job and start saving - its what I'm planning to do and what most of my friends did.
"If you'd been listening, you'd know that Nintendos pass through everything" - Jack O'Neill, SG-1