Hi Ed,
As far as I am aware, there are no means to enable Internet communication
over a firewire interface. This interface is designed to interface digital
cameras, external drives and some printer/scanners. It is not designed for
communications purposes. Although you could use USB (there are some USB
modems available), you will get the best results if you use the LAN interface
as it is designed specifically for communications purposes. What is the
speed of your Internet connection? It is probably a lot lower than the 100Mb
LAN interface, and, as such, is the limiting factor. Upgrading to a faster
interface such as Gb LAN (1000Mb) will not provide any benefits unless your
Internet connection warrants the increased speed.
Dwarf