Easiest thing to do is sell the TP card on e-bay and get yourself a pcmcia card with BNC. Most of the big networking companies make them. This will allow you to simply add on to your existing network without any reconfiguration of software or topology. I am not a big linux guru but I think you can have as many network adaptors in a lin box as you have space for. Additionally if you connect 2 NICS together via CAT(X) with an RJ-45 connector you need to use a crossover cable.