Ok, the kit comes with a very short network cabel (should be cat 5), but if your planning to use it you'll probably need a longer one cos we're talking no more then 2 meters of length (use google to convert that to feet and inches if you want to know).

Now you mention a cable to connect to your modem, but what kind of connection does that require? USB? Network? Because if it is a USB you'll need to either buy a router or new modem with Network Jack.