Yeah you're right this particular JVC doesn't support AV-IN.
I don't know of any device that will concert your analogue signal off-line from a PC. (Although I will be happy to stand corrected from others).
There are plenty (Dazzle and Pyro to name a couple) that will take the signal to a PC.
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.