Hello Tina... from what I know the 457 we had was an "Empoyer sponsored Bussines ( Long stay) Visa"... under the skilled workers temporary visa options..
I sure do hope yours will be as quick as ours too. Have a look at the list of documents etc required to change from your SIR 495 to PR and no harm in getting it in order now:))). That would make it much faster because thats where the waiting is, I believe. Good luck