You'll have to read the novel if you want to know what happened to Jill. They also explain what happens to Angie as well.
As far as why she wasn't in the movie, Sienna Guillory wasn't available to do the role. She was too busy filming Eragon at the time.
However it probably wouldn't have been much of a hassle just getting someone else to play her role, or better yet at least mention what happened to the character rather than just taking her out completely.
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"You know, I've been to Hell. And I didn't see your Clothesline anywhere." - Kane to JBL