First thing I would do is look for the programme you want to copy on torrent sites, someone else has probably already done the hard bit.
Unless you have recorded free channels all Sky premium channels are encrypted on the hard drive, so you need an active Sky card and a Sky decoder to view them at a later date - the only way to get the shows off the box is to use a third party recorder, as in that article - or do what stopme suggests and just download copies of the same programs from Torrent sites.