Windows 7 has a cool new feature that should help. Click the icon in the taskbar to ensure that the program has focus. Then hold down the Windows key and press the right-arrow a few times. That should move the window across your screens and eventually bring it back onto the screen that is still active.
http://social.technet.microsoft.com/Forums/windows/en-US/f3040564-0457-4c91-af71-dce1bc673a99/moverecover-offscreen-window
