Seems to me that you should prepare and file a Florida Family Law Rules of Procedure Financial Affidavit prior to the hearing, as your ability to pay is a critical issue in this contempt proceeding.  In fact, that's exactly what the letter says.  Additionally, you should plan to appear at the hearing.  I'm sure that the rules of your house arrest allow for you to attend court hearings for which you are compelled to attend.

Really, it's all right there in the letter...