I lost my passport and had to pay the full price to get a new one. New passport starts from the date you apply not the dates of the old one so you will receive a new 10 year passport but they are expensive now. Just go to the postoffice and get an application, there is a part on it where you advise you have destroyed or lost your passport.
Just looked up the cost for you.
77.50 for standard service
112.50 for one week fast track and
129.50 for one day service BUT FREE if you were born before 2 September 1929, in other words if you are 80 it's free!!!