I'm a veterinarian in the USA and have been involved in shipping cats and dogs from America to rabies-free areas like Hawaii and England. It is a complicated and multi-step process. First, nobody can back date your rabies titer test results. The official government form is dated, and even if there was some way around that, faking the test date would put the veterinarian's license in jeopardy. Even if you were my best client, I wouldn't risk my career for you. Second, keeping a zoonotic and potentially epidemic disease like rabies out of a rabies-free island country (or state) is a serious thing. Nobody screws around when it comes to rabies.
Is your dog's epilepsy controlled with medication? If he doesn't have seizures very often (less than every three months) and is well-adjusted, he could be cared for by a close friend, family member, or responsible, bonded pet sitter. If he is in poor health, ask your veterinarian if s/he can do long-term boarding at the hospital or clinic.
If there is no other choice, look into him staying in quarantine in Australia for the first three months of your stay. It is my least favorite option, but better than trying to sneak your dog into the country. Remember what happened to Johnny Depp and his wife when they broke the rabies protocol.