If your router supports WDS (wireless bridging), you can bridge two together and hook the other up to the ReplayTV. The schedule updates are much faster that way and you can pull shows off the Replay onto your laptop using DVArchive, as mentioned above.
I have 3 Buffalo routers that are bridged together. One is connected to my cable modem and the other two are connected to my ReplayTV units. I can also stream shows from one to the other that way also.
AVSForum is a great resource.