Upvote:4
You will almost assuredly be denied admittance if you arrive in Australia after your "Entry Expiry Date." If your flight to Australia is so delayed on departure that it will arrive in Australia after the "Extry Expiry Date," the airline will refuse to allow you to even board the flight.
A search of Australia.gov.au returns nothing about amending or changing already-issued visas. That's because — as @k2moo4 notes in a comment — Australia law does not permit the amendment or change of visas already issued.
That being so, your choices are:
or
or