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I am afraid that the only way to change the deed to the proper heir names is through opening of probate. Because the deed is in your step father's name and his current spouse and was never changed over to your step father and your mom's name, this is going to be a major issue, since their estates are going to have to be probated as well and you are looking at 3 probates and the fact your step father never put your mom's name on the deed would mean that it would go to the heirs of your step father and his first wife by law unless he had a will that states his share went to your mom and in that case you would inherit that share of the property, but because the name of his first wife was on the deed as well, her heirs could have a claim as well.
I am afraid, that because multiple estates are involved and you cannot represent them pro se, without an attorney, this means that you will need to engage a probate attorney to file probate and get the deed cleared and placed in the name of the proper heirs.
I am afraid to say that just because your mom's will stated you get the property does not mean you will automatically get the property if she never received ownership rights in the property from your step dad because he never changed the deed to add her to the deed.
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