I think you'll have to register your Kindle to your account. I see in another thread you don't have wifi, so you will need to log into your Amazon account from your PC, goto "Manage your Kindle" and hit Register. You'll need the serial code of your Kindle.
From there you should be able to buy Amazon ebooks, download them from your account and copy to your Kindle via USB.
Unfortunately I can't help about the Kindle PID.