AirTrain to Jamaica Station. Then, Manhattan-bound "E" train to Roosevelt Avenue/Jackson Heights, and transfer to a Manhattan-bound #7 train to 33rd Street/Queens Boulevard. If you want to avoid taking two subways, you can instead take a Manhattan-bound Q-60 bus from Jamaica Station to 33rd Street, but the bus ride will take longer.
Note that if your particular destination on Van Dam Street is not close to Queens Boulevard, you might have a long walk (or short taxi ride) to get there. Map the location on www.mapquest.com to see how far it is from Queens Boulevard.
AirTrain to Jamaica Station.