I'd try a couple more times to try and get a good quote, as that seems fairly high. For example I am 22, 40% NCB, and drive an R33 GTR with a few mods, and im only paying $1700! Car is insured for $40,000.
I am in the country, and i have a clean record, so maybe that has something to do with it?
Maybe try to get a higher no claims bonus? I joined just cars with 3rd party only (on my old r33 gtst) for 2 years, and then upgraded to comprehensive, and they convert over the NCB from third party to comprehensive.