What derailer hanger do I need? (screw on derailer is bent) I'm hoping for some help with repairing my bike. My derailleur hanger snapped recently. I think it should be easy enough to replace with the right advice.

I have a picture of my previous hanger. It has 3 pins to attach to the frame. Does it matter if the replacement one looks the same yet only has 2 pins? Are they fairly universal?

If it looks the same like, this one on wiggle, would that mean they are the same? (i.e. the holes don't come at different widths apart?)

When my derailleur snapped, it came off with a lot of force and ended up bending a screw. Again, image attached. Can anyone tell me what this screw does and if being bent will be an issue? Also is there somewhere I can just buy a replacement screw if it's important and I can get it out. I would rather not have to replace the whole derailleur.
With respect to the bent screw, it's called the 'B-screw' and yes it is important.

The pivot in the derailleur where it attaches to the hanger is the 'B pivot'. The screw adjust the spring tension and controls how close the top jockey wheel comes to the largest sprocket. 

Assuming your derailleur was adjusted correctly you can leave the bent screw in place temporarily.

Online bike stores in the US don't seem to list replacement b-screws (or derailleur limit screws), but they would be a standard metric screw or bolt size (Googling bike discussion forums seems to indicate M4), so you can get a replacement of the appropriate length at a hardware store. A stainless steel one is probably a good idea.