Atheism is about wether you believe the proposition or not, agnosticism is about wether you know the proposition to be true or not.
The agnostic says that he doesn't know enough to accept the proposition, the Atheist says he doesn't believe the proposition. They are the same thing. You are just saying you don't know and don't believe the proposition rather than just saying you don't believe the proposition. It's the same thing. It doesn't change the conclusion.
A theistic agnostic is a bundle of contradictory nonsense. You can't believe it and know it not to be true. Those are most commonly known as the closet Atheists.
I don't know if you catched my previous post but this page i linked before explains all you need to know.
Hmm, would it make more sense to you if i said the baby is an atheist but he doesn't know it? I am not sure why my previous example didn't click though. If i say not believing the space cow means you are a "atheist-moo" but i didn't tell you, would that mean you are not a "atheist-moo"? It is not dependant on you recognising the term yourself, it's about your belief of the proposition.
I'd say that yes, it does mean I'm not an atheist-moo, since I wouldn't even know of the concept.