sorry I can't answer that question since I neither know what Telstra Australia changed nor which bands and WWAN technology they offer now.
You'll need to find out which GSM and/or UMTS and/or LTE bands you could use, and then compare to the P*S8 WWAN module series at http://m2m.gemalto.com/products/m2m-advanced.html and check the bands those modules support - particularly we recommend the PLS8-E, PLS8-US, PXS8. When you found one of the modules that matches your needs, you order your Neo900 with the according module.

BR
jOERG