For bricks and mortar retail (or most industries), costs scale with population size: a larger country requires more stores.
For apps, there is one relatively fixed development cost, no matter how many customers you have access to. It costs roughly the same to build the app whether you've got potential customers numbering 1 million or 100 million, so you're likely to get a lot less bang for your buck in a smaller geographic market.
Would you rather build an app for the US market, or Liberia, yet Liberia has a higher population density.
It sounds like you want to build store finders, to me this would mostly be boilerplate with a few images and a different location db for each store.
Build one store finder and then go shop rates around that reflect the fact that they are all the same. Heck it could mostly be done in HTML which means you can do a jqTouch app instead of Cocoa Touch.
Is there something about Australian businesses or addressing that would make abstracting these details impossible?