What parts do I need for belt tensioner problem?

[guyever]

The problem first appeared today as i was at a drive in restaurant and noticed some motor noise as i pulled up to the window. Thought it must be the guy behind me, but quickly discovered i had no one behind me so it must be me. Got home and popped the hood and quickly noticed a slightly wobbling tensioner pulley. Stopped the engine and saw a few, very small, shiney, metal flakes scattered about. I can wobble the pulley a little by hand. Of course my first action was to log onto ShopForum and see what you guys had to say. I did a lot of searching, learned a heck of a lot, but couldn't quite get the answers I needed. What parts should i order? do I need just a pulley, just a tensioner? what about the shock? I really need to get these parts here post haste so I'll need to order early tomorrrow morning. My guess is that it is just the pulley, but it would be prudent to replace everything as the car has 77,000 miles on it. Am I right?
Thanks
Guy