How to generate Good sounding audio books?

1) How to add more voice engine in MS-Windows-Xp-prof, free of cost? At present it has only MS-Sam installed.
2) Will it help in generating mp3 audio output using the "Daisy Pipeline>creation>simple>narrator " procedure?
3) The output quality of my projects generated using the aforementioned route with MS-Sam TTS voice engine is not as good as is available in the Amis demo project of "Three little Pigs". In this latter project, do they use machine generated audio or it it human dubbed audio?

Thanks

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