Electronic Circuits and Projects Forum

hi, im just wondering if i could make a speaker for my pc using a car speaker, a headphone cable, and some component which i think is an amp, its works sort of like a resistor which i got from an old speaker. it has the 2 cables which go into it which give it the power from a house plug, it then goes into a coil of copper wires like a resistor and then 2 small cables comming out of the other side.
i know that the car speaker wont be able to run from the power comming from the headphone jack of my computer. i want to know how i give the speakers power using that amp thing and were and how do i plug power it up to my speakers, is there another wire inside the heaphone wire were i can link the amp to? give me some set of instructions which i can follow, im still king of newbie at electronics. thanks