I think you're posting to the wrong forum, this forum is for users of software by a company called Saberlogic. You're better-off asking somewhere like TechRepublic.
Nevertheless, it sounds like you're needing a router to distribute more than one connection from your phone line. Given the small difference in price, I'd recommend purchasing a "Modem Router". The difference is that it houses a both devices, keeping things tidier and less complex.
For best results, contact your ISP (BT, Virgin, PlusNet, whoever) and consider revising your service package and choosing an option with a free wireless modem router (such as BT's HomeHub III). It may even save you money.
Good luck!