The O-A multi-entry from Australia does not require you to have any money in a Thai bank account, only sufficient funds in Australia to meet the requirements. If you use the multi-entry wisely you can get 2 years from that visa. I would suggest that you look at the O-X from the Thai Consulate in Sydney, not Canberra, far better visa for long term.
Are you applying through Sydney or Canberra? Yes it makes a difference, in Sydney someone will answer the phone, in Canberra you will get a message only. Although Canberra are reasonably responsive to emails.