I use Airprint for Windows. Works without any problems. See
AirPrint on Windows and elsewhere.
If you want to play with the network adopter priority order in Windows 7
1. From the "Network And Sharing Center" window click "Change Adapter Settings"
2. On the "Network Connections" window, press the ALT key on your keyboard to being up the menu bar
3. Click the "Advanced" menu and then "Advanced Settings"
4. In the "Advanced Settings" window you will see the "Adapters and Bindings" tab and under "Connections" you will see the order they are in, you can use the arrows to the side to move the connection priority up and down.