Its a pain in the ass but if you use Windows you can setup internet connection sharing on your laptop and install a second network card (pcmcia or usb) with a cross over cable to the Tivo.
Can you connect to the network using wireless? If so then you could use the wired port to connect to the Tivo and not have to spend any money! Also realize the tivo only needs to download data a couple times every 2 weeks (it holds 2 weeks worth of data).
Can you connect to the network using wireless? If so then you could use the wired port to connect to the Tivo and not have to spend any money! Also realize the tivo only needs to download data a couple times every 2 weeks (it holds 2 weeks worth of data).