Online booking - change to price

[Iheartchristmas]

I booked a car hire for April 2011 in Oz.
I was quoted a good price (which I now know was really really good) but have never booked a car before and thought booking in advance and for that long must have been some type of offer.
Anyway, booking came in at 350 Australian dollars for 30 days.
I booked the car hire. Have a reservation number and booking acceptance email with this total price.

I have since received an email from the car hire company and they are telling me that the rates published on the internet were wrong. A problem with the total sale price and that I can have the car hire but at a much higher rate (3 x the price!)
Any ideas where I stand?

[WestVirginia]

How much money have you paid up front?