You could contact Kingston for the sound card or scour Ebay for a replacement(second hand) sound card but in essence you're going to have much fruition if you got a headphone splitter and paired it with the headset and your existing soundcard on your system.
The USB driven soundcard processes all the audio via the USB port and the onboard sound card is rendered useless. In hindsight, the USB driven sound card only emulates/virtual upmixes stereo sound to a surround sound stage.