It isn’t too late, but you should hurry.  Here are two form letters I found today in Florence that will help you do the trick:

My rough translation: Dear Father Christmas, my name is ……………I am writing you because I have some wishes that I hope to have realized and I know that you are very nice to good children.  For Christmas I would very much like to receive…………………………………………………………………………………………………………………………….etc.

Thank you in advance for fulfilling my wishes.  I promise you that I will be very well behaved and always obey mamma and papa.  I give you a big hug.  My address is…………………………………………………………………………………………………….

With affection (signed) ……………………………………………………………….

If I were you, I would hurry and get these letters mailed!