Best to obtain a co-sponsor in your situation, unless you want to have your current assets (whether in the US or in the land of down under) taken into consideration (messy, will only take into account 20% of fair market value of each current asset - isn't it simpler to find a co-sponsor to file another affidavit of support alongside yours?)
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First, you must establish domicile in the US which means you have to move back, get a job, an apartment, bank accounts, etc. regardless of how much money you make or how long you have been out of the US. Secondly, unless you have earned less than required, you stil must file a US tax return regardless of where you live. I am more concerned about the domiclie issue however so that needs to be addressed immediately. good luck.
My colleagues are correct:
1. You have to demonstrate domicile in the US ... filing non-resident US tax returns is not good.
2. You probably need a financial co-sponsor. Or, you can preceed your wife to the US ... start working and then submit pay stubs and an employer letter. How long? I believe that the instructions refer to 6 months of pay stubs.
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