post a pic of the back of your radio.
If you look at the top pic, there are some grey/black male hrns's at the top. There should be some black female hrns's that plug into those to allow the front speakers to play.
What wires are the bostons in the back connected too? Is that the speaker wire they ran from the dash? Dig around under the rear deck and see if you can find two grey two pin plugs that would normally hook up to the factory tweets. They are actually clipped to the top of the rear deck so you might have to fish them out but try and locate them and see if anything is hooked up to them.