Assuming your amplifier that is hooked up to your subwoofer is a mono amplifier, you need a second amp (2-channel) to power your front components. You could also look at a fairly high powered 4 channel amplifier to replace your current one. Run the front two channels to your new front speakers and bridge the back channels to get double the power for your subwoofer. Either way you go, you will have to run another RCA cable to the amplifier because currently, you only have the subwoofer output from your head unit and you need the full range output.
