Sin City (possible spoilers)
 

Well, I saw Sin City finally even if its been out for 2 months and theres something I didn't understand in it:

How is it that Elijah woods Character and the Big Muscular guy who got the death penalty are both alive at the end again in that bar?

Also, who is the chick that plays becky in the movie (the chick that betrays all the prostitutes and is in the elevator at the end on the phone)

Because shes incredibly hot and most sites ive gone to only list the names of the actors not who they played in the movie so i can't figure it out.

http://www.imdb.com should answer your second question...

as for the first, my take on it is that things don't necessarily happen in the order in which you see them in the movie.

http://www.imdb.com/title/tt0401792/fullcredits says becky is played by Alexis Bledel

This is a spoiler.
 

The scenes aren't necissarily in chronological order. The movie is split up into three stories. (as are the comics, so I hear) These characters are fine and well in the bar because the third story ends at the beginning of the first. Sort of Pulp Fictionesq.

(bare with me here, I may be wrong in a couple of details as I saw it the night it opened, and have yet to read the comics.)

^ No, that's right Cello. The stories happen concurrently to an extent, so that's why Marv (Mickey Rourke) is in the bar when Hartigan (Bruce Willis) walks in, and Kevin (Elijah) hasn't yet been "dis-armed."