Help setting up speakers!

[Karthik 2.0]

Okay I'm sure you've seen speakers(4.1) that connect to the subwoofer and the wire to the soundcard is only 1 green wire unlike other speaker set out there which use 2 wires or 3 wires for 5.1 settings.
Problem is I'm getting front sound from the rear speakers as well but no rear sound at all. Is there any way to fix this problem?

Okay, you still don't understand my speaker settings? Well this should help:

Edit: spelling error for "souncard" it's "soundcard"!