I tried out a Trek with Bontrager women's handlebars. I loved them.

How do I measure my current handlebars?

What does Anatomic 75mm and VR85 mean? Where do you measure to find out if they should be 400mm, 420mm, 440mm, 460mm, or 380mm?

How can I be sure my brake levers will fit? Do I have to consider changing any other parts, headtube?