if theres only 1 pair rear preout... u can just use a splitter and connect it to both fron and rear channels of the 4 channel amp... connect the front of the amp to the front speakers and the rear to the woofer.... just make sure ur amp has that switch for the sub (forgot what its called).

rear speakers connect to player and u should have a good sound staging...

only thing to make sure is that ur amp is powderful.... otherwise itll end up cutting off if it gets too hot or during serious bass sections of the song... like what happened to me last time.. my solution i ended up getting a monoblock