I just had the same problem. I used to use the usb to connect to the controller and today I just bought a usb bluetooth adapter and windows would think its a motionjoy hardware. So this is what i did . Keep in mind that there's probably a faster way around this but this is hw i got it to work....
1. I opened up control panel>hardware and sound>devices and printers. I then plugged in the adapter and checked to see which new hardware windows installed. I then right clicked on each of them hit properties , selected hardware tab, and clicked properties again. on the next box either click on the "change settings" in the general tab. If you dont have that button (im on win7) then select "driver" tab. On the next window click uninstall . do the same thing for each and every hardware that shows up in devices and printers when you insert the adapter. next
2. unistall motionjoy
3. insert your adapter again and install the drivers that came with it.
4. Install motionjoy , and load drivers. then after its done go to bluetooth pair and you should see the bluetooth adapter listed . connect your ps3 controller via usb and then click "pair" ...... after that you should be good to go