Most dongles should be fine , You need the following..
1. A Blue Tooth Dongle that's preferably supported by BlueSoleil , although if you are on Windows 7 you don't need to use the WiDCOMM/BlueSoleil Bluetooth stacks it should auto detect
2. Once the Bluetooth dongle is installed you are going to need to go to "Find Devices" once there it will poll for a device press and hold 1+2 buttons on the wiimote then wait your adapter should detect the Wiimote
3. Don't pair there are no useable pairing codes for the wiimote right now..
By "pairing" I mean the pairing code , each wiimote has an individual pairing code to pair it with your bluetooth reciever , it is not used on windows/doesnt do anything so just press "Skip Pairing" during the device install screen , you might also need an External Sensor Bar these can be purchased for roughly $20 US you can also use 2 candles with various candle lid type devices/things and get your infared signal from that
Hope this helps
PS: Yes your wiimote will work fine , not sure if the wii microphone/headset is supported on Dolphin/PC unfortunately though