subwoofer, amp

ok this is what i have currently and its no longer hitting enough. i want some more bass. i have alpine CDA-9805 single output Bazooka EL series seems to be a 8 or 10 inch. Alpine MRV-f302 amplifier. ok i had this setup when i bought the car. so i left it in there. as far as i know, the amp powers the speakers, and there are some RCA cables going to the bazooka. the tube seems to have an internal amp....correct me if i'm wrong. what is the best method for me to switch my sub. is there a way for me just get another bazooka tube that will kick a little harder? the tube i have now doesn't have the normal sub connections, power and ground but has a electrical connector, and RCA cable. if there is a way that i can just get antoher bazooka tube that can kick harder i rather do that. what about the tubes that do not have internal amp? how do they work? if i get another sub not a bazooka tube. i want to keep the MRVF302 to power my speakers. if i get another deck, is all i have to do is just connect one amp for the speakers to one of the outputs, and the other output to another AMP for my sub? i'm not that good with radio, elctronics. any help would be great.