Smoke coming from beneath the alternator

Hi Fanatics

I drive a 2001 320i e46.

Last night as I got home, I noticed that there was a little smoke coming from under the hood of the car. I checked and because it was dark, I couldn't really make out where it was coming from - So I bled the radiator then topped up again after the smoke and steam had settled.

This morning, I started the car and heard a little rattle coming from the front. I drove from Northcliff where I stay to Randburg that's when I saw the smoke again I parked the car and investigated. I noticed that the smoke came from underneath the alternator and the one "wheel" (I've attached an image of what I'm referring to) is wobbly and that's where the rattle come from. Oh, and there is a little water leak. I was told by a friend that it may be linked to what's happening with the alternator.

What needs to be changed and what am I looking at paying?