If you just want a matching size rim (gts style but not roh) try 0408 396 327 think the blokes name is shane and he imports pontiac rims/parts /cars has been in the industry for a long while and is based near canberra if ive got the right advert. Another spot worth try maybe one of the wheel manufacturers like dragway they re-rim wheels if you had a 14 x 6 wheel to redo.The cost would be high though too and from NT depends how much / soon you wanted it.
Wheels unlimited or wheels australia cant quite remember the name but their based in Ballarat Vic and did advertise on Ebay.They redo / restore old mags (somebody here will know who I mean) if they dont have any or do them might have a lead for you. All would be more than swap meet prices though.