'88 lebaron aftermarket deck problem

I just bought a cd player for my car and connected all the wires but none of the speakers are working. The back speakers are infinity speakers, the front 2 are blown. My old radio/casstette player works fine and if I connect the cd player to a speaker from my stereo in my house it works fine. I'm thinking I'll just get some new speakers and rewire everything. Is there an easier way to do this keeping the old speakers?