Funny thing about the Tempeh in Coles/Woolworths/Safeway; they used to be in pretty much everyone but now I hardly see it. Maybe they cut down on stock due to bad sales.
What suburb in Vic do you live?
Tempeh is easy as to find! Generally I can get in any Coles right beside the Tofu. Spotted it in a few health food shops too.
Seitan though is another story! I see it in so many recipes from the US, but I've never tracked it down in Australia. I believe Radical Grocery store in Brunswick may stock it though, but I've yet to check them out: http://www.radicalgrocery.com
I live in country vic, so coles does not stock tempeh, I checked tonight.
But il have a look in some melbourne health food stores this week, and look for seitan too.
I just saw that the radical grocery store sells it, I havnt been there for awhile so looks like il make a trip. I highly suggest that store to anyone who hasnt been.