This is a potentially serious matter on a number of scores. You must contact a New York attorney as soon as possible. Do not depend on an online answer in deciding what to do here -- it could affect your future very significantly.
The letter is from a law firm that does nothing but send threatening letters (and in increasing amounts), trying to get you to pay whatever they want. There have been articles where the firm is quoted as saying they send in excess of a million letters, but have only filed around 10 lawsuits.
The letter has absolutely nothing to do with the criminal case and can in fact hurt you if you pay it - it can be seen as an admission of liability.
Deal with the criminal case if and when it comes up, but the letter is just a threat that rarely, if ever, gets backed up.
Palmer, Reifler & Associates, P.A., is real and is a legal firm.
That firm is often hired by stores to bring civil complaints against shoplifters and others that have tried retail theft.
They have been sued for their practices.
Check with a lawyer in your locale to discuss more of the details. Several on this website Avvo have suggested to ignore the letter. You should phone a NY attorney and seek advise from an attorney licensed in New York