You can go to the Supreme Court in New City 2nd floor....
You can order your marriage certificate online through NY State Vital Records at vitalchek.com, for a fee. Or you can order the certificate in person at the town clerk's office that issued you the marriage license. Nyack is in the town of Orsngetown, however, if the license was issued by some other town, that other town would have the certificate.
Thanks! Your answer is awaiting moderation.