The best book/tape series I know of is CURSUS LINGUAE LATINAE VIVAE, put of by the Familiae Sancti Hieronymi (–Jerome in English) in Clearwater, Florida. It’s 13 tapes and a big paperback back. Cost? About 70 bucks. Steep, but worth it. You HEAR the language and learn to THINK in it. The speaker is a Carmelite priest and the focus is on Latin as the living language of the Catholic Church.
If you’re not ready to go that far, you could start with LET’S READ LATIN by Ralph MacInerney, the philosophy prof at Notre Dame (and author of the Father Dowling mysteries), a paperback/CD set that teaches you several prayers and helps you work through a few Scripture passages as well as short texts by (if memory serves) Augustine and Aquinas. Again, you HEAR the language, and you learn prayers so that you can say the Rosary in Latin.
Hope you find this helpful.