you plan to credit transfer to other unis or stay with UniSA?
Well pretty much the difference will be the exposure you can get in Aussie. Then the fees are of course a few times more than if your stay in Taylor's University.
If you go over to Aussie you will also have more choices for electives and majors while if you stay in TU you can only take electives from other business and mass comm UniSA programmes.

you could use to TBF to apply directly if you would like. Most unis from the Group of 8 and ATN does accept TBF. The only one among them that I'm aware of that doesn't accept TBF is UTS.
If you want to spend one year in Taylor's University first then go ahead.
Through the UniSA programme they have articulation agreements to transfer to UTS,RMIT,UQ and UWA and you can also still do credit transfers to other universities. Some have credit transfered to Monash,Adelaide,Melbourne etc. with no problem though sometimes they have to repeat one or two units that didn't get exempted.

You didn't wait long enough. It will arrive in the mail. I believe when you applied the site stated how long you may have to wait (close to a month?), and unfortunately that is accurate - it does take quite some time. No need for concern.