[stomachmonkey]

It's a weak cell or terrestrial signal, not weak WIFI but that really means nothing.

What I get from your post is you would like to load up your phone with songs and play them back using your new Android head unit.

1st, assuming the head unit supports BT which is highly likely, you should not need any additional apps.

The stock default music app on your device should be all you need.

As far as BT in general. I would not look at that as the 1st option for connectivity.

Highly probable the head unit has a standard 3.5mm audio jack, USB port, or even an SD card slot.

SD card would be my 1st choice. Load it up, slap it in, let the head units UI handle playback.