If you are willing to work nights, there are TONS of p3 cases around Brooklyn- and you may even be able to get groups together.
I know this personally, because I myself had to turn away many cases because I could not fit them into my schedule.
Once you get the case, all you have to do is get the p4 authorization letter from the parent, and send it to the Board of Ed along with a copy of your license. Then the BOE will send you an approval letter and then you are all set!