new Xfinity Gateway

1) I got a text from Xfinity asking if I would like Xfinity to ship a new Xfinity Gateway at no additional cost. I would like to take that offer now. How do I go about doing so?

2) Also, my home's internet speed has been slow, which I am not sure if this is a separate issue from the Xfinity Gateway model.

3) Also, also, I get no wifi when I am at the end of my room or when I am in my back porch. I don't think it is reasonable for the signal to go completely out when I am literally still in my room.