I'm not ready to forgive her,what should I do?

After hubby confesed in Jan last yr that he & my younger sis had slept together in 2005-6 each time she visited us on sch holidays I asked her not to visit anymore, stopped communication & almost divorced him.I'm still hurt & feel betrayed by both of them.She hasn't shown any remorse instead she told me "I don't care If u don't want to forgive me my God will, plus I'm family one way or the other,someday u'll need me"

She just called me today,to tell me she has a 3wks old baby girl wth her new man.I have nothing against the innocent baby but the thought of seeing her(the mother),talking to her makes me sick.We haven't really talked since the confession(almost 2yrs now)but it still hurts like it happened yday.In short I'm not ready to forgive her what shld I do or say,shld I do something for her baby or just forget the 2 of them?

Update: November 10, 2009.
Thank you all guys for your responses,it's pple like you who keep me going.To the sarcastic ones wait till you find yoselves in the same situation then you'll know better than just the 'why did you forgive him and not her' attitude.