It is preferable to lein the HafTarah from a Novi. Even a printed Novi is usable when it contains the entire sefer. The particular HafTarah printed in the Chumashim is not preferred. If the Shul does ...
There seems to be a wide range of customs with regard to reading the haftara. In some shuls (mostly Chassidic) the one who is called up recites the berachah, and everyone then says the haftara quietly ...