Old Etrex - $100, has two spare AA batteries taped to the back of it.
Garmin Forerunner 201 - sits on dash or yoke - $200.
Then.........
1. Use Snagit and take screenshots of the ERSA VFR waypoint pages.
2. Use an OCR program to convert them to text.
3. Edit to remove page headings and numbers.
4. Import the text to an Excel spreadsheet (excel is smart enough to parse the stuff for you).
5. Convert lats and longs into whatever format is required for Ozi explorer.
6. Export as a comma separated flat file into Ozi Exporer.
7. Upload waypoints to both Garmins. (you have a 500 waypoint limit, so do it by states).
Voila! Your own Australia Wide personal database. Total time, about two hours.
CAUTION: CHECK THE WAYPOINTS AND ROUTE ON OZI EXPLORER AND A PAPER CHART BEFORE USING THEM!!!!!