What kind of rates can i get as a bad driver?

I am 17, and crashed my dads Porsche twice. So, he has kicked my off as a second driver. I have had my license for about 6 months now, and I am stuck driving his older Vette (2005). I don't have a credit card yet, cause my parents are worried that i am going to crash it too. With 10,000 miles on it, and it being bank financed, how much can I expect to pay on it? Or know of a way to make sure I am getting good prices? I went shopping at Geico, but the rates were ridiculous.
I live in Omaha Nebraska.

You forgot to mention what type of coverage you are looking for. Full / minimum? And if you want a small/large deductible. But if your vehicle is financed, chances are you need full coverage. What about grades? Just try using Yahoo or Google to get some quotes.
Decline the add-ons, and high deductibles for the best savings.

Your best bet is to read up on this stuff a bit as doing so could really give you an edge on reducing your rates in half, or more. Here are a couple decent recent articles from Cheap Car Insurance and another from Edmunds.