I have a 1996 Ford Explorer Eddie Bauer edition, does not have the jbl audio system. I have installed an aftermarket radio, gives out 60 watts and has two rca outpts in the back. I have the stock amp.I am trying to install an aftermaarket sub, its a sony sub 12" 1200 watt peak power 350 watt rated power. What is the cheapest way to get this sub hooked up?