Checking some google on the subs you have.... That AMP is way underpowered. You're not gonna get anywhere the bass you're looking for. We're talking 20w amp to 800w RMS speaker. Also, it's a car sub/amp... This is gonna sound stupid, but goto a music equipment store where they sell guitar amps, you can get a "cheap" bass amp that'll sound fantastic and give you plenty of bass. Bass guitar amps are meant for raw bass, usually have a small tweeter to handle highs, a simple EQ for mixing, a built in headphone amp, and since they're made for professional use, they'll last you years and years. Expect to spend 100 - 150$ for something big enough to move you. As far as the computer speakers go... Just get a 2.1 kit. There're a million of them out there, buy eBay or craigslist if you'd like, that way you can try them out first. The two car audio ones you have listed both need boxs and to do them proper, you're looking at 100$ in lumber and a good hour or two of construction.