Limey getting married in New York

I am visiting NYC for a week in early January and we have decided to get married when we are there.
There will only be the two f us plus two friends and we are going to have a family party when we get back to the UK

I have done quite a bit of research online and found out how to get a wedding license. I suppose as I am coming from abroad my only option is to have the ceremony itself at City Hall as well as getting the license there is to go get the license and return a couple of days later to get married. Unless any brides know of better places to actaully get married that I can organise from the UK ?

I know that I have to pay using a money order? I know this may sound stupid to you but where do I buy a US money order.. are they easy to get?

I will be flying into NYC thursday midday and likely get married following monday.

I will be looking for local stockists of flowers and for a hair salon to do my hair . I will be staying near West 56 Street.

I also will be looking for a nice place to have take photos and have a meal afterwards so any suggestions will be most helpful.

Thanks so much fellow brides and nice to meet you

Wendy xx