How do we settle the estate of my deceased father?

My father was in Florida when he found out he had terminal cancer, a doctor told him he had 1 month to live. From the time a doctor told him and the time he passed away was 4 1/2 months. When he thought he only had a month to live he married this lady in January 2013 who he was married to only 4 1/2 months before he passed away, hurried and sold his home in February 2013, may have changed his beneficiary on his government retirement savings, and changed his Will. A Will has not been produced since his death June 4, 2013. She is trying to claim everything, and she may have influenced him since the cancer had invaded his brain. How do I find out who his retirement went to? He had never paid child support, his only two daughters from a prior marriage are adults and have a claim against his estate. What is the best possible way to handle this?