NYC is tough for ultimate, there's not much field space, I had no idea so few city colleges had squads. I know Columbia and NYU have teams,
I think MUD is the best place to play in the city
http://www.manhattanultimate.com/, great people and a good level of play. I haven't played with NYCPUL, but they had a winter league in brooklyn that's well worth looking into.
I've been told that WUDI is even a step up from that, but I haven't played to confirm. It's the bigger though, which normally means more competition. You can get to the fields from the Metro North and a short bus ride.
What Borough are you coming from SirWatson?