Also, try calling the housing department of Yeshiva University.
Speak to your student services rep or whomever is in charge of housing. I know quite a few universities (i.e. - Columbia, NYU) and colleges have some sort of off-campus housing buildings, tips or lists for brokers willing to discount their commission. If that doesn't help, feel free to contact me via email and I can do a preliminary search in a brokers' database. The Manhattan rental market is competitive so it's best to get your "ducks in a row" before starting your search.