Hooking up radios plz i need hlp?

ok i have a x.m radio it is old delphi silver radio.....xm skyfi. i got a car kit for christmas like a year or so ago and just never had time to ook ti up well i am trying to put it in a pontiac grandam 2001 we had to repalce the radio from stock to a kenwood it has a c/d player now the car kit i have the power cord plugs into the cig lighter outlet socket and then the antennea i have them 2 cords plugged in andi have power and signal ......... now the hard part to me comes up how to get the sound into the speakers in the car..... it came with like a tape you stick into the tape player and then it will work but in the caar that i am going to be driving dosent have a tape player how would/ could i hook that up where i can have musics the outlet that it is on the (car cradle) is called the LINE OUT plug in so what so i need and how do i hook it up ......... and if you could ow much would the things i need to get cost