Have you got Nokia Map Loader installed on your PC?
1.You can buy a licence which the time scale ranges from 3 days to 3 years,which gives you navigation and instruction voices.
2.You'll know if you've paid for it as you can only istruct the device to do so.
3.To have the correct maps isn't hard,if you need australia then download australia from the Nokia Map Uploader.
More info and lots of threads in the GPS section
http://www.n95users.com/forum/gps/