Greg,
The other guys may be able to offer you more in a way of flight school knowledge etc etc however I can give you some real and recent info on the visa and working situation here in Perth. So long as you do your three months I have not heard of 417visa extensions being declined, the six month thing does ring true as do the comments about finding a decent job as people are put off by your 6 month limitation.
Rent can be relatively high depending on how far out you live and many jobs like you to have a car (ease to get around - obviously) but what I have found is that with little experience and just some enthusiasm you can get a labouring job, driving etc which will pay reasonable well ($22-25ph). You can do this for six months no problem in the city. Should you need to then go and do you regional work there are plenty of places just outside Perth where you can do that and still have a local airfield. Alternatively you could head elsewhere to do this. As the guys have said above most towns have an aero club (I did my regional work in S.A, local club was naracoorte).
Possibilities are always there, you just have to work for them! Good luck