It seems you're looking for a pivot shoe and a new pivot bar, which is the part that fits into the window. I won't be able to identify what you have based on these pictures, though. I need you to tell me what the thickness and width of the shoe is. You may want to remove it before you measure to ensure that you're as accurate as possible. I will also need to see a picture of your pivot bar removed from the window.
Thanks for the response. I am not sure how to get the pivot shoe out of the channel. There is not gap along the channel big enough for me to take it out. Do you know how to get it out? The only two ways I can think of is to take the window apart, or breaking the channel to get it out, which I don't think is a good idea.
Thanks in advance.