Currently Being ModeratedApr 8, 2012 7:16 AM (in response to Churchbell06)
You can only deauthorize computers you still have physical access to. If you have reached the limit of 5 authorizations and need to authorize yet another machine you can always use the deauthorize all option described in this Apple support document. This procedure can only be performed once a year.
As for your other problem, see this older post from another forum member Zevoneer covering the different methods and software available to assist you with the task of copying content from your iPod back to your PC and into iTunes.