G'Day Robbo
The Passes are Available on the Department of Environment and Conservation, Climate Change and Water NSW( National Parks and Wild Life Service) web site or from their offices, the closest to you would be Murwillumbah, There is one at Byron Bay and Alstonville and the Kiosk at Woody Head near Iluka http://www.environment.nsw.gov.au/annualpass/WhichAnnualPassShouldIBuy.htm, I just worked out how to copy the web address that takes you straight there, If you have a consession card you have to take it with you for proof, its a bit of mucking about however if you stay for more than a few nights a year it will save you so brass and trying to find the right change, hope this is helpful
Grizzly