I would check the Texas Board of Legal Specialization (http://www.tbls.org)and search for a board certified probate attorney. I did not find any in Grand Prairie, but there are many in the area. The website has an interactive map so you can locate an attorney closest to you. You will have to ask if the attorney charges for an initial consult. Many do.
You can check Avvo.com, lawyers.com, Google.com, the Texas Bar Association, and other sources to obtain the names of attorneys who handle contested probate matters. Some attorneys provide a free initial consultation and others do not. You must ask the attorney prior to the initial conference if there will be fee charged for the first visit.