Casey already has been arrested three times, on a broad range of charges. The key ones are Child Negligence/abuse, and the financial check fraud charges. At this time she is out on bail and is confined to her home via electronic monitoring.
The State Attorney is taking his time to do things right. They already had an early error that is effecting how and when they charge anything further related to Caylee's disapearence or death. The very early on charged her with child neglect. While fully appropriate at the time, it bumps into a few quirks of Florida law. Under Florida law the state must be preparred to bring her to trial within 120 days of when she is charged. The defense can choose to waive this speed and go for a longer date, but they would not in this case for the neglect charges. So there is a court date 2nd week in November.
Problem 2 is because the child neglect charges are part of the crime that would also be charged as a homicide, if they are brought to trial, jeopardy will acrue, and the state will not be able to increase the charges to homicide. If the charges are upped to homicide before the neglect trial starts, then the clock starts over at 120 days.
Since the clock is already running LE wants to burn off as much of the current timer, strengthening their case, before they reset the timer and have to go to trial for homicide within 120 days. (A fast trial puts the prosecution at a disadvantage).
So current bets are, unless they have an absolutely iron clad case, and probably a body, they will hold off on charging her with any homicide until the first or second week of October. If the body is found or further damning evidence is revealed then they may feel comfortable to do it sooner. But figgure that October 16th or so is probably their drop dead date on which she WILL be charged with something more serious.