Hmmm, theirs a whole bunch that could be causing your problem in this scenario. Can u get internet with your virtual vista ... if so that meens Vista is connected to the router ... if not u may have to somehow bridge your virtual NIC card with your Macbooks wireless card.
I have never used an airport before .... but I am assuming the printer gets an IP address (if your connected to the network and am able to get to the internet than try adding a printer through the TCP/IP port indicating the IP address if the printer (however I admit to not knowing anything about how the Airport works with the USB port for printers + I have lost all confidence with Windows and quit useing the OS entireley and at this point would not be any sort of an authority on Vista at all!)
Or this could all be pointing towards an issue with Vista and a whole bunch of incompatible hardware, being that the OS is still extremely unreliable and oddly enough probably has more hardware compatibility issue than that of even Apple products itself!