My father passed away seven years ago. Everything went to his surviving spouse( my stepmother) and she is now wanting to sell the house. There was no will and the house was bought in Georgia in 1979.
There's something wrong about this. For starters, I assume that your father and stepmother were not yet married when the home was acquired in 1979. If that's not correct, then my comments below will change.
Under Georgia law, when a person dies without a will and is survived by a spouse and descendants, the spouse and descendants share the estate (the spouse will receive either 1/2 or 1/3 of the estate, depending on how many descendants there are). Since your father died without a will and had both a surviving spouse and at least two surviving descendants, there is no reason why "everything" should have gone "to his surviving spouse." You will need to clarify how this happened.
A realtor contacted me about signing paperwork to sign the deed over to my stepmother and she required the signatures of myself and my brother for her to sell the house because it was bought in 1979 and there was no will. If my brother and I don't sign over the deed (as we were his oldest children whom he left in the divorce) what will happen. Will she still be able to sell the house and if so would we be required to sit down with her in probate court.
I don't know what you mean by "sit down with her in probate court." However, I'm
guessing that title to the house is only in your father's name and that the realtor understands that, when your father's estate was probated (if it that ever happened, which I'm
guessing it didn't), you and your brother should have received a share of the title. As such, your stepmother cannot convey good title without your and your brother's cooperation.
It's obviously impossible for anyone here to predict intelligently what will happen if the two of you decline to cooperation. I suggest you consult with a local attorney.