So, the moment has come when my passport has expired, but I can't now return to Russia. What should I do?
I see no other way out of this situation, except to return back to Russia. But try googling just in case.
You don't have to go back to Russia. I also live in the United States on a permanent basis and thought it was time for me to buy tickets to Russia, but then I accidentally found out about a company that works with the consulate and can start updating your documents. In short, read more info here, it is a very user-friendly service indeed.