I'm currently going through the "TheNewBoston" C++ tutorials (Link at the end of this paragraph) and finding them easy enough to understand, I feel like I have some basic knowledge in C++. I was wondering how much knowledge do I need in C++ to start game programming in C++ because that was the main reason I wanted to start C++, was to learn how to create games. I would like to be a game programmer if you haven't already guessed it. http://thenewboston.org/list.php?cat=16
Beginning C++ Through Game Programming by Michael Dawson
Excellent book for you.
As for your questions... you need a full knowledge of all of the C++ basics and a full knowledge in a 2D Graphics API of your choice. I recommend SFML. It comes with 2D graphics rendering, networking, an event system, an audio package, thread management, as well as OpenGL integration.
Don't even try SFML till you know all of the c++ basics. You'll be dead in the water if you do. You're hair will turn gray.
So should continue to go through the tutorials I am currently going through until I have a full understanding of each tutorial then get the book or get the book now?