I advise you to seek local criminal defense counsel. Since you say that you are unwilling or unable to do this, I will offer you advice based on the limited information you've provided. You don't mention exactly what you were convicted of though I assume it is a felony sex crime of some sort. If the charge "wobbles" (i.e. it's a charge that can be sentenced as either a misdemeanor or felony) than you will be asking the court to reduce your conviction from a felony to a misdemeanor under Cal. Pen. Code 17(b). The judge is not likely to do this if you have not finished paying your fines so I strongly advise you pay off your fines before filing this motion and being heard by the court. Additionally you should write a well thought out letter to the court that is attached to your motion for 17(b) relief. This letter should not read as an attempt to minimize culpability and you should not suggest that you're entitled to relief because you're "not a scum bag or anything." Be contrite, show what positive steps you've taken since this incident, and why nothing like this will happen again. Additionally you should attach character and professional reference letters with this motion. These letters should demonstrate your good character, they should not talk about about the crime you were convicted of or attempt to diminish your responsibility. I will repeat, you stand a much greater chance of succeeding if you hire an attorney. You provided limited and incomplete information, you may not be entitled to relief or you may have to employ a different strategy. You should have an attorney represent you in this. This is not an easy task, your motion may be rejected for technical or procedural reasons and most judges simply don't rule favorably when defendants attempt to represent themselves. Good luck.
People commonly talk about two kinds of probation: adult probation (reporting) in the case of felonies and conditional sentencing (on misdemeanors). You cannot convert one to the other if I understand your question correctly. If you have felony 17b'd then your probation status will change as a matter of law. However, not having paid your fines, you will not be able to terminate early although under the right circumstance you could have your charges 17b'd.
You need to ask the Judge to 17B the case...reduce to a misdemeanor. That would end your formal probation. Judges are not always inclined to do it halfway through the completion of Formal Probation. You would better be served by an attorney.
Seth Weinstein, Esq.
Southern California Criminal Defense
This reply should NOT be considered a legal opinion of your case / inquiry. At this time I do not have sufficient factual/legal documentation to give a complete answer to your question and there may be more to the issues you raised then I have set out in my brief reply.