Hi
I don't know if its doable, but what about approaching dog related magazines and asking them to do a small write up on you promoting the business or even
perhaps some of the more senior members could write in recommending the site..
It wouldn't have to be limited to dog mag's too.. That's life, etc seeing as dogs are a pretty common family thing also!!
Also what about dog shows? Would you be able to sponsor them (not sure on the costs)
Also, approaching online business (and 'real' businesses) like it seems you have done asking for sponsorships yourself, and perhaps they could have a link to your website (affiliation) or fliers/business cards..
You could approach rescue groups all over Australia and offer a write up about their business to make people more aware (also offering to put up 'help wanted' on the forum?) in exchange for them directing people here?
Approaching specialty groups like GSDWA *for example* asking for cross promotion?
Sorry I didn't see the last thread (wasn't here!) so some of these might already be in place/already suggested/tried and tested.. Just some ideas i thought of