Coffeeintotheorems response is quite good.
A very important piece of information which I don't see in your profile is the status of your recommendations. How enthusiastic do you expect your three recommendations to be? Which courses did those recommenders teach?
I lived in Philadelphia for a long time, my family is still there, and I have friends who have done grad and undergrad at Penn. The area near Penn is not a war zone. Parts of it are rough, but it's fun and there's tons going on. Maybe it would be worth e-mailing a current grad student to learn more about affordable housing.