Hearing a "tick/knock" sound at idol
 

Hi all, since I bought my car there has been a little tick/knocking sound coming from the engine bay at idol, it's not a very acute sound but its noticeable. I removed the AC belt and discovered that the bearing was bad in it, so I eliminated that variable but I'm leaning more towards the power steering pump making the the noise.

Last week when I changed the oil in my car I realized the power steering pump belt was half off the pulley, so I put the belt back where it belongs and it seemed fine but two days ago the belt actually flipped over, but stayed on the pulley, and now I noticed that the pulley on the pump is wobbling a little. So my questions are, could the pulley be the cause of the tick/knock noise, and where should I go to get a new pump if that is the problem? Thanks.