The answer to your questions should not depend on where your divorce was finalized but where the decedent passed away and the location of the property. If the estate is going to be probated, you should be able to file a notice of claim with the court where this probate occurs. The local court may have forms that are downloadable from the Internet or you may possibly be able to obtain an appropriate template from the court itself.
So you should first contact the local court with jurisdiction over the decedent's place of residence and file your "Notice of Claim" there. However, I would highly recommend that you contact a probate attorney and get more detailed advice on the specifics of your situtation.