I you want to add to your question, the best way to do it is by replying to the original question, not by posting a new one.
What equipment do you have at the moment? Presumably either a combined modem-router, in which case you can connect both computers to that, or a USB modem. If you have a USB modem, then the only way for both machines to access the net would be by means of connection sharing, which is not an ideal solution, and would require that the machine with the modem was running before the other machine could connect. Your best option is to get a combined modem/router.