The regional airlines are sponsoring Australians on the E3 visa. I know a couple of fixed wing guys who have recently gone to the USA on this visa. The helicopter companies either don't know about this visa or they don't want Australian Helicopter pilots working there.

If you have the desire and $'s you could always retrain in FW acquiring an F1 visa and associated 2 year work permit. After completing your FW training you may be able to then switch back to a Helicopter job using the FW related F1 work permit for a couple years. If you have significant prior helicopter experience added to the 2 year F1 work experience period you may have achieved enough experience and qualifications to qualify for the National Interest Waiver Green Card if you're serving the U.S population in some capacity through flying helicopters. Worked for me. Good luck.