As with everything in NYC - stuff like this you do over the phone.

First find a halal butcher and ask if they deliver - next call the restaurant - epxlain your predicamenet and indicate that there's a halal butcher in New York that will deliver the steak directly to the restaurant. Doubt they could refuse and I could see no reason why this would be in violation fo the health code.

Lastly, I wouldn't be surprised if they tell you its a common request - e.g. many lunch carts serving meat in the city have halal written all over them with big letters. And I would guess that there are a bunch of halal restaurants all over the city (Persian/Afghani kebab places, etc.)