How do I connect my xbox 360 to the internet?

I have had my xbox for awhile now and Its time I connect it to the internet so I can play live, only thing is my cable modem is way on the otherside of the house. What do I need to do? I have no internet ports where my xbox is, I dont know what I need or what to do all I know is I need to buy the xbox 360 wireless deal that plugs in the back, but I dont have wireless internet dont know what kind of router I need or even how to use one. I would greatly appreciate any help.

Thanks