Q: Bluetooth only works up close

My problem is my new Magic Mouse and any other bluetooth device only works or pairs if its sitting in the mbpr. It shows a signal of around -80 to -90 when on Mac move to the side and stops working. Ran all hardware test And shows everything is fine. It's sitting at a Mac repair place now and they tell me no hardware problems trying to find a software fix! Really if it don't work why not just switch out the wifi/bluetooth module? Anyone have this problem