Hi there and welcome to this place.
I have a very similar JVC turntable in the QL-70. Not that different to your own, presuming it is the same as in the library here. If so the headshells are pretty common having an SME bayonet type fitting. As an example:http://www.needledoctor.com/Gemini-HD-1 ... tegory=432
A bit on the expensive side of the story, but you can find similar a lot cheaper on the likes of E-Bay. In the UK as cheap as $10. Pay a bit more though and get better quality. Depends how much you want to budget and how much do you want out of this deck. I have often seen genuine JVC headshells on the Bay.
Cartridge, again budget matters, but at the cheaper end of the scale I’ve always thought the Audio Technica AT 95 to be great value and a good all rounder. Again gets you started without breaking the bank. I am sure other good alternatives may get mentioned here: http://www.needledoctor.com/Audio-Techn ... tegory=402
As for the feet, that's a different kettle of fish. I have the same issue with one of mine. I haven't looked at repairing it yet (don't think it will be too difficult), but a replacement will be rare if you want a match or expensive if you are to look at alternatives. I think you may find they are a 6mm thread.
Alternatively you could do away with them altogether and look at mounting the deck on the likes of these Bright Star Isonodes. I think are the same as the UK offers, but simply sit the deck on them. Very effective. http://www.needledoctor.com/Bright-Star ... ategory=88
I guess the total picture depends on how much you want to spend and how original do you want it to remain?
A starter for ten here and see what others might offer with their knowledge. Plenty of that on here.