You don't need a modem-router combo, you need a router. That has the connections you need and comes with an installation instruction.
Just go and buy what you need.
ok the internet input in my modem+router (belkin n150) has the telephone line input. but the cable internet connection i got has slightly bigger wires coming out (sorry for my wording i really dont know their names exactly) those big ones get connected directly to my lappy (hp touch smart tm2) but not in my modems input (they are getting fixed in the output sockets). so my question is how can i go wireless?? have heard many places that many routers can recieve net connections via there output sockets too. i have tried googling it out but due to lack of my technical wordings im not able to get what im finding plz help me out.