Boardwalk Empire Season 1 & 2 Blu-ray is $48.70 inclusive of shipping@ Amazon
You can get Season 1 & 2 of Boardwalk Empire on Blu-ray for just $48.70, inclusive of shipping charges. These are region free so they can definitely be played in Australia.
DVD Land has it at $72.95 before shipping while it is $69.99 before shipping at Mighty Ape. The next best price I found was $62.08 with free shipping at The Nile.