It sounds like you have a Cable Modem, since you said you can move it to the other cable outlet.
Can you tell us the Model number of the modem?
Most modern routers come with instructions and a CD. Usually all you have to do is plug your computer into the router, then put the CD in your computer, then the CD will tell you what to do next.
You will need one ethernet wire to go from computer 1 to the router, and one ethernet wire to go from the router to the modem. Then you will need one long ethernet wire to go from the farthest computer (computer 2) to the router.
Here is a link to get you started, How to Buy a Wireless Router | PCMag.com
usually the more you spend the faster you can go.