Need Help - MN

I have hit a wall. I am looking for my birth sibling. We share a father and I have never known about her until recently. I have very little information and My father isnt giving much. Birth Mothers name was Martha Nordstrom That was her married name and her name at the time of birth. She lived in Saint Paul MN at the time in the 800 blk of Bush Avenue. (next door to where we lived) She had an older child name Butch. My birth sibling is female and would have been born between 1965 and 1969 My father says the sibling was married approximately 20 years ago but would not provide her name. Just that she lived in MO at that time I have done extensive searches and even tried to obtain old land records. Any help would be appreciated, even if it seems like a small piece of info Thanks