In general, Berserk doesn't cover the whole manga. Some storylines and details might be missing or adapted differently for various reasons, like production constraints or creative choices.
No, the Berserk anime doesn't cover all of the manga. It selectively adapts certain parts, and some crucial elements and developments from the manga are absent in the anime version.
At the moment, there's no definite information on whether Berserk manga will continue. It might, but it could also remain unfinished. A lot depends on the circumstances and decisions of those involved in its production.