B1/B2 Visa change to Work Permit / Finacee

[D34]

Current holder of B1/B2. I have just completed 6 month visitor stay on this visa. I have been told that I must stay out of the US for equal time, 6 months, before returning to the US. My boyfriend (US Citizen) and I (Australian) are looking at different options so I can return to the USA sooner. Finace Visa, Work Permit or getting married (outside of the US) and applying for the Spouse visa. Looking for suggestions on what is the better way to make this happen. Would it be easier, as a current USA Visa holder, to apply for a change in status or are we better off applying for completely new visa?
Thank you forum readers!

[immihelp]

Get married in the U.S. and apply for green card.