The law permits a sentence up to one year in jail and a $5,000 fine. A court rarely imposes this maximum sentence. A person can be assaulted without being injured. It is rare, but occasionally a prosecutor can proceed with a case with other evidence at trial if the complaining witness does not appear to testify. Often if the witness does not appear, the case is dismissed at the time of trial.
Any prediction of the actual sentence a judge would impose turns very much on the specifics of your case, the judge who decides, and the judge's impression of you. I encourage you to get a lawyer and discuss the specifics of your case with him or her.