Here are the audio recordings for Book 1 in mp3 format, for downloading and listening off line. Remember, the text and audio is also on the following playlist on YouTube:
https://www.youtube.com/playlist?list=PLqszOrihESDm81eFbA6Z2ykCgSfjf7f_q
No matter whether you use the mp3 files or the YouTube videos, it really is imperative that you use some form of audio when reviewing the textbook readings. It is only by engaging your ear (and also repeating the Latin aloud frequently) that you will actually own the language.