Left prong is broke off the machine plug.

If the power inlet on the actual machine is broken, you will need to find a local Janome dealer and see if the part is still available to order, or any sewing repair shop that deals in servicing all brands may have an old one from a deceased machine that will suit you.

I am not familiar with this model in Australia, it may have come out with a different code reference here.

Phone around locally is my suggestion, we here come from all around the world.......beyond the oceans of where any of us call home !!