Studio System Help

[MRPPony]

Okay so I'm in need of some assistance about sound hookup.
I want my computer to have a subwoofer, preferably 10" or more (just because I like to make noise), but the only sound systems I can find have subs that are 2"-5". I have a 5" sub that came with a Logitech 5.1 Surround and this thing's output is just sad. I got an aftermarket sub which increased the bass a bit, but yeah not enough power.
So can someone help me in what I should get? I don't mind switching to a 2.1 since I've yet to notice anything that much different with 5.1 vs. stereo besides being slightly louder in the mid-treble range.

[derpytunes]

I have my computer hooked up to my home theater receiver. That allows me to add whatever size sub I want. A little pricey, but it sounds awesome!

[MRPPony]

Oh? What type of cords are needed? Cause I just took a look behind a Denon Receiver and wasn't sure what I'd need to hook it up to my computer. Like do I need something with a special sub cord or anything?
Mind posting up a picture of your hookup?