Audio Systems: amp and sub hookup question, rca cables, rca outputs

Question
hey i bought an amp and a sub with hopes of being able to make my car share with bass! But the sound sucks. Im wondering if you could tell me the best LPF HPF GAIN crossover combination for bass, and the places to install the wires. i have a koiiler xm-7676 600 max power 2 channel briged amp and a sony 12" xs-L1237 xplod 1100w peal powser single sub and a 12" enclosure and the way the guy that i paid to set it up did it was, he hooked the amp up to the sub, not to any of the front or the back speakers.
On the side of the amp where the right left hookup is both positives are hooked u pto the amp.Like i said im braindead at this, and i want killer bass.
I have factory 20W deck and speakers, but i was told that with the amp and sub i got i could do just fine. Please write back and answer whatever you can.
                           thanx,
                              Gary

Answer
Gary,

  i never recommend installing aftermarket amps/subs with factory units .. but what you need is a converter box *10-20 bucks* at radio shack tell them you need a converter box to turn your hi-level speaker inputs into RCA outputs they will know what you mean .. now with this you will need to splice into your cars rear speakers + and - wires and wire into the converter box if you need help with the color codes www.streetdreams.com/wires should help you out .. now the converter box will want connections from all of your speakers but you dont have to do this just double up the connections from the rear speakers just make sure you keep the sides together when you wire up .. now after this you will need a set of RCA cables that will now plug into your converter box then into your amps RCA connections .. this gives you sound .. now for your amp your sony xplod should be wired in bridge mode which means with your 2 channel amp the + connection should be on one channel and the - channel on the other channel read your amps manual to make sure it is able to be wired in "bridged mode" after this turn your GAIN control about 1/4 turn , set your crossover to LOW and adjust your frequency to around 70 or 80Hz *1/4 a turn usually* .. if you have any BASS boost controls leave then alone for now .. turn on your head unit turn volume up to where you usually listen to .. go back to your amp and turn the GAIN up until you get distortion then back off an 1/8th of a turn .. this should fix you up .. hope this helps you out if you need anything else let me know

thanks