Craigslist and the other usual sources of rentals. She will be one of tens of thousands of young people in NYC that are crammed into lofts and apartments together. She can expect to pay $1500 a month to live on a couch in Brooklyn. That's the reality, I've never known anyone in NYC that has an extra room for a friend, much less a stranger.
Unless of course you know some Russian billionaires with apartments laying around in NY. Now would be the time to hit them up.