Alison
The title of the book is "Medics At War", subtitle "An Abridged History & Anecdotes of the 2/13th Field Ambulance 1940-1945", author Len McCarthy, ISBN 0 646 26471 0 (Hard cover edition),
0 646 26728 0 (Soft cover edition).
Depending on your location you may be able to view a copy at your regional library, or as well as Ebay you could look online at something like Regimental Books Online or Military Books.
As mentioned by Trevor earlier your grandfather's service records aren't on line but you can request them from National Archives of Australia by email to
archives@naa.gov.au or write to
PO Box 7425, CANBERRA BUSINESS CENTRE ACT 2610, AUSTRALIA
I have tried to attach a scan of the page, please let me know if it doesn't happen.