I agree that learning styles vary among people. What works for many is listening and reading at the same time. This is probably why there are so many videos of language lessons (e.g. on You tube and elsewhere), that have subtitles in the language you are trying to learn (that is, you can read exactly what you hear). This is no hard evidence, of course, but the fact that this sort of learning material is widespread might indicate that there are a lot of people who find it useful.
In your case, finding a printed version of the audio books you have could be helpful. For some, silently opening your mouth with the speaker/actor, while looking at the text, helps improve pronunciation. I know it seems a bit funny, but it won't hurt to try it.
For spoken language, conversation is very important. Audio books are great, but if you could discuss what you listened to with someone, it would do wonders for your spoken English.