Bluetooth Control for Amplifier

I made myself a stereo cooler and would like to have some bluetooth capability so I do not have to physically connect my phone through an aux cable to the amplifier. The cooler has two speakers connected to the amplifier and the amplifier has an aux connection to connect to audio devices. I would like to use the Aux connection and connect it to a circuit board for audio output. I have a USB bluetooth adapter and would like to use it if possible as an audio input. What would be the best way to do this (also cost efficient)? Any ideas?