You need to ask this question also on the immigration law section. The only way not to have any potential immigration consequences is for the charge to be dismissed or if you are found not guilty. Even if you go through a pre-trial intervention diversion program, Immigration and Customs can use your application, which requires you to admit the crime, against you if they decide they want to. So consult with an immigration attorney about your own goals and circumstances to make sure you handle your case the best way.
As far as your case as a strictly criminal law matter, the best way to have it resolved is obviously if the State Attorney's Office (prosecutors) drop the charge. They look into every criminal charge in order to decide whether or not further prosecution is warranted. If your incident was really a "misunderstanding", there is a chance that the prosecutors would decide to drop it. You likely will need a criminal attorney to speak with them about your version of the case and provide any evidence or witnesses that support you, since the prosecutors usually don't want to speak to defendants outside of court, and it is never a good idea for the accused to speak to the authorities about their case.
If you cannot get them to drop your case and you are unable to do a diversion program due to your visa expiring, there is a good possibility that you can get a fine and a withholding of adjudication (which means you aren't technically convicted) from the judge at arraignment. However, be aware that even a withhold of adjudication can have future effects on your immigration status in the U.S. Good luck!
It would prudent to talk to a criminal defense attorney down here in Miami/Miami Beach.
You are right, the Court Options diversion program does take some time and you may not be able to complete all the conditions before you leave. If they require classes that go beyond your departure date you could have issues. Also, your case may be defensible and you may be able to just do nothing if the attorney can break the case down.
You have options, and as i tell all my clients down here, it is only the first page of the book. Once your attorney gets a look at the police reports he should be able to tell you the best course of action. If you can swing it financially, you should seek help and not just show up to the arraignment unrepresented. If you have counsel you do not even need to attend the first (and most) court hearings.