Have you begun applying for jobs? Do no limit yourself to NYC. Northern New Jersey has a lot of IT companies and is literally less then 10 minutes by train from Mid-Town Manhattan. Ask your HR department if they have a subsidiary in NYC that will allow you to transfer. Other that the best I can say is that times are hard here in the US where jobs are few and far in between.
Moving from the UK to New York to work is essentially impossible. First, there are almost no jobs available in the U.S. Second, it is illegal to work in the U.S. unless you obtain the necessary visa before you enter the U.S., which is also almost impossible to obtain.