Mac Forums

I have a cable modem that feeds into an Apple AirPort Extreme and a flash drive plugged in to the usb port. I can access the disk when I am on the AirPort's network, wifi or wired, I know the IP address and had no trouble mapping a network drive to it on my Window's 7 computer but when I try to access the flash drive from another network or anywhere away from home on the same computer I cannot connect to the disk. When I try to map a new network drive, with the same technique that worked at home, it fails. The error report shows that my computer finds the network and the disk but cannot connect. I tried a few ways of using the AirPort password, using an AirPort Disk password, and different ways of providing credentials and changing settings on the AirPort itself but was unsuccessful. I have the AirPort Utility and Bonjour installed on my computer.
Is there a way to access my airport disks when not on my home network, away from home, without buying any extra devices?