Does drawing a card end your whole turn, or just prevent further movement?
You can take any other action, even though you're not allowed to move anymore.

The keyword you are missing in the rules you quote is "can": 


  You can perform actions (such as using an item or attacking) in the middle of your movement.


This is simply clarifying that it is allowed to do actions in the middle of movement, it is not a restriction that they can only be done then. You can also do actions before or after movement. 

See the rules that allow other actions, on page 4 of the rulebook:


  ON YOUR TURN . . .
  
  … you can do as many of the following actions as you want, in any order:
  
  
    • You can move.
    
    • You can discover a new room.
    
    • You can attempt a die roll.
    
    • You can use items or omen cards.
    
    • You can attack (once during your turn after the haunt starts)
  


This means that with things like closet and vault, you can attempt to access them immediately. Same goes for attacking after moving as far as you can. 

The only thing that drawing a card or running out of movement points prevents is moving.