How can i get my ipod to play in my car?

i hav a 5th gen ipod nano. its the 1 with a built in speaker and video camera. the prob is, the speaker isnt strong enough to play may music well enough. i hav an audio to audio cable, but my car's stereo doesnt hav a port for it. the stereo only has a cassette player. it also has radio. then, connected to it, is a 6 cd player thing. thats in the trunk tho. please help me, driving has gotten so boring, and music sure would help. thanks.