First question … what is the output from the camera … RCA video plug, S-VHS, … ?
Adaptors from most formats to USB are available, just need to make sure your computer is fast enough to keep up with the video stream.
Once you've connected your video camera to the computer you'll just need some appropriate software to capture the video stream to disc as an AVI, MPG, MOV or whatever, this may well be supplied with the adaptor.
Video editing software may also be desirable, to trim/edit the resultant files and maybe even join them all together.
It's all very straightforward … no need to involve your Pentax camera at all, filming off the TV would only ever be unsatisfactory at best … try it with a normal TV program to see the results