No, the CPC Study Guide is not supplied by the school. You do go over all the same material, but since I am waiting to take the certification test I thought I would benefit by reviewing another guide.
It's not easy to say how long it will take you to finish the course. You work at your own pace. I work and do volunteer work, so I finished more slowly.
I would recommend completing the early courses as quickly as possible. The actual Medical Coding sections (1 and 2) are much more challenging and you'll want more time to take them (twice to three times as much time).