I forgot to mention that if you're looking for a good general campaign history focusing on Australia's military involvement in Vietnam, then "Australian Military Operations in Vietnam" by Albert Palazzo is pretty good. It is published by the Australian Army History Unit, and details (including purchasing links) are on their website:
http://www.defence.gov.au/ARMY/AHU/Operations_i... The book includes descriptions of the Battles you're interested in (Long Tan and Coral/Balmoral), as well as others (including Binh Ba that I mentioned above). It also gives descriptions of equipment and organisations for the Australian Task Force.
Hope that helps.
cheers,
bish