I was hoping to hear from you before responding further to this question, because if you were charged with filing a false police report or for anything else, for that matter, the penalties vary from state to state. However, this charge is typically a misdemeanor. Also it's non-violent and that's imprtant too.
Generally on a non-violent misdemeanor or first felony offense, the possibility of serving an incarceratory sentence would be just about zero, unless you took the case all the way to trial and lost the case or you warranted and failed to make your court date. If you are charged, you should have a criminal lawyer representing you, in order to get the best possible outcome, but if probation is what you want, your lawyer should be able to get it for you.
That said, if you didn't know that your car was wrecked in your own alley and someone took your car, wrecked it joyriding and limped it back, you may want to fight this case. That's another reason you should have counsel to make sure you're as informed of all of your rights, choices and chances for success before you make any decision about the course of your case.
If you need clarification or a follow up, please reply here on this question thread, and I will respond.