My sister has charges of 2 counts of grand theft, how much time is she facing?

Your question requires an attorney consultation. It is not a simple question that can be answered on this type of forum. There are many factors that would need to be considered and evaluated. Does your sister have any criminal history, and if so, what is it? What is the value of what was stolen? What are the facts and circumstances leading to the charges? Since we do not have all the facts, it is impossible to give a meaningful answer. In any event, your sister needs to retain an attorney and I strongly suggest that she contact an experienced criminal defense attorney for a face-to-face consultation and give him/her all of the facts surrounding her case. The attorney would then be in a better position to analyze her case and advise her of her options. If she cannot afford an attorney, she should ask the judge to appoint the public defender's office to represent her. Under no circumstances should she talk to the police or anyone else about her situation without an attorney present.