Can you blackmail her??
Seriously, we at Gothamist understand how rare it is in NYC to find cheap apartments. The best way to go about an apartment search is to contact via email all of your , colleagues, etc--basically everyone you know in or around NYC--and let them know you're looking. It is often these people, and not strangers off of Craigslist or who saw your posting in the local coffee shop, who can provide you excellent last-minute leads. Perhaps your friend utilized her insider resources.