Playing music via Bluetooth in my car

I have the newest iPad. Previously played my iPad 3 music in my car via an aux cable but since the new iPad doesn't have that feature, I connected with Bluetooth. However, it only plays a handful of songs. The same songs. I check to see if they were downloaded, but it only shows 3 songs, so it can't be that. When I click on a particular song, it says to download it. Why is it playing only a certain # of songs and how do I get the other songs to play. Out of the blue one day it started from the beginning of my song library and played each one, which didn't make sense, either. Any ideas? Also is there a way to batch download all at once? I don't have time to click on 1000+ songs to download individually.

Thank you.