Dr. Derek Enlander in NYC has spoken about the use of sublingual (methyl?) B12. He uses a spray that you apply under the tongue, and claims good results from that. You can probably find some of that somewhere, or even order it from him.
You can also buy sublingual methyl B12 lozenges that you put under your tongue and dissolve.
Unless you have a deficiency of intrinsic factor (which allows for absorption of B12) supplementing oral B12 is probably sufficient to get your levels very high if desired. If you have a deficiency of intrinsic factor and hence pernicious anemia, you may need injections - but they should be covered by your health care plan (I don't know Australia well but it's hard to imagine any country denying B12 to people with pernicious anemia). Oral supplementation generally works fine in other cases.