sorry but LOL
OK, you haven't quite got the concept of what 2.1 speakers are.
2.1 speakers are essentially the same as "basic twin speakers"
You have 2 speakers (the 2.1) that provide the highs and the mids for the left and right channels and then you have 1 subwoofer (the 2.1) which provides the bass for both left and right combined.
The theory being that your ears can't tell what direction bass is coming from so you don't need to provide left and right bass.
So 2.1 speakers are only standard 2 channel stereo speakers and just plug into your normal headphone/speaker output on your computer.
the speakers that need special outputs are 5.1 and 7.1 which have extra rear and middle channels/speakers to provide full surround sound.