I dont beleive there are any shops still trading Amiga products in Melbourne. Have you tried any of the still active Amiga user groups?
http://www.aug.org.au/they might be able to help...
maybe
http://mc1.boing.net/or a long shot is
MVB Computer Supplies Pty Ltd
506 Dorset Road,
CROYDON 3136
ph 03 9725 6255
they used to supply Amiga bits upto last year or so
Az
