Whenever I try to import video, I can get the video just fine, but no audio
comes through on preview or the final product!

I am using rca composite audio input in stereo (i have a HP pavilion media
center PC), and have mic in/ line in selected for my input source.  

Any assistance on how to get audio to come through would be greatly
appreciated, as I have tried almost everything, including other programs.

PS free solutions would be preferred.