Not sounding facetious is difficult here, but the biggest thing wrong is you bought a DVD camcorder, the things are a liability in my humble opinion.
Anyway, can you just clarify what you're doing? Have you shot some more footage on to a new disc and you can't get the computer to recognise it? It's just that your say 'new disc to record my film', which sounds like you're recording something back to your camera, but you say 'import to my PC', which is going the other way. Could you clarify that for us please?
But seriously, if you have the opportunity take it back and get a MiniDV cam, you'll be happy you did in the end.
Sorry, but I like to talk straight and cut to the chase!