You need to go to your local China Town and get the real poison the type that Amazon/Walmart wont sell. Roaches start moving out on their own when they see that stuff.
The only thing that worked for me was sealing up holes, and that wasn't 100%. I tried the genetic-warfare gel that others here are talking about, and it didn't seem to work -- it could've been working, but being in a 6-floor walk-up meant there were probably millions of roaches to take the place of the dead ones.
The other thing I noticed is that whether you have roaches in NYC is a complete crapshoot -- I lived directly above a bar/restaurant and had zero bugs of any kind, and I lived with no bar/restaurant in sight and had a roach problem. Go figure.