Why is Audio and Video out of Sync during recording?
You should check your recorded video with MediaInfo. Regarding your problem, it shows,


if the durations of the video and the audio is the same or not,
if the interleave of the audio (the starting offset) is set correctly
in which sampling rate your audio was recorded.


Then, I would import your video file into Audacity (which imports only the audio, of course). 


On the left side of each track you find the sampling rate, too. Is this the same sampling rate as being reported by MediaInfo?
Does Audacity play the audio too slow, too?


My impression from the symptoms that you describe is that the audio is recorded at a certain sampling rate, but reported as a lower sampling rate, or not at all.

Try to modify your sampling rate, either in your recordings settings, or in the Windows system. On Win7, it's under Control Panel->Hardware &amp; Sound->Manage Audio Devices->Recording. There, select your microphone, then Properties->Advanced. There you can change the sampling rate.

If changing the sampling rate doesn't help, then you can only try another webcam software, or record the audio independently.