1.) It's my guess that Selina Kyle is sent inside prison as a diversion: to help Bane with his movement and be an inside help to let everyone in Blackgate free. Very much as it was in the beginning of Knightfall where Bane busted open Arkham and the Joker took control of letting everyone else out free.
2.) She might shoot some one... but I'm thinking it's the same awesome violent factor similar to the magic pencil trick: it was reported awhile back that in some of the fight sequences (my guessing the one in the second trailer) Catwoman fights brutally and jams a pistol into a guy's eye socket. Rumor has it Anne was really into it and accidentally bruised the poor man's eye in the fight.
