Bit of an update for those in a similar position to me... I don't know how valid the source is, but gives me some hope...
Marina Brizar, head of corporate and private client at immigration law firm Playfair Visa and Migration Services, said there was a grace period for people currently on 457s to apply for permanent residency. The changes to residency eligibility will not kick in until March 2018, so 457 holders have until then to submit their residency applications. In a statement, the Department of Immigration and Border Protection confirmed this.
"Existing 457 visas will continue to remain in effect until they expire. As is currently the case, a 457 visa holder who wishes to remain in Australia beyond the validity of their current visa, must apply for a new visa before their current visa expires," a department spokeswoman told HuffPost Australia.
"Existing 457 visa holders and applicants as at 18 April 2017 will continue to have access to existing employer sponsored pathways to permanent residence. Further details will be published on the Department's website in due course."