I received SS without sitting the IETSL. Your sister will need to apply to AITSL for a skills assessment. You might also benefit from contacting AITSL and assessing what further qualifications she needs, if any. Their turnaround for assessment is 12 weeks. I have been teaching in WA for the past 3 years after completing my studies over here. I did my first year in Perth and then chose to venture more remote. After 2 years remote I have my permancy with DET and love it so much that I'll stay on next year. Teaching, both high school and primary, are in demand in WA . By 2015 year 7 will no longer be primary school, but secondary and there will be a high demand for high school trained teachers in the public system (as most private have already changed year 7 to high school).
Best of luck to your sister!