Texas: Looking for siblings/birth mother

(Written by a friend helping with the search) I (Michelle Ann Koepke West) was born January 23, 1959 in Harris County Texas to Floyd Donald Koepke and Mildred Lucille German. My birth father kept me and raised me. I only found out two weeks ago that my stepmother is not my birth mother. Am now looking for birth mother (who we believe is possibly deceased) and half-siblings. We believe Mildred Lucille German (birth mother) was born December 24, 1931 in Van Zandt County, TX. She was married several times -- at LEAST twice prior to marrying Michelle's father, Floyd Donald Koepke in Harris County, TX on 12/24/57. One prior marriage shown in Harris County was to a Melvin Cooper in 1955. We believe she had a son born of this marriage named Melvin, Jr. We believe he was kept by his father and raised by him. Another son was born -- name unknown -- from another marriage or relationship who was "given" to Mildred's sister Anita and her husband Bill Bisker or Visker. Both this son and Melvin, Jr. would have to now be in their mid to late 50s. A daugher was born to a man perhaps last name Martin. She also would be in her mid to late 50s. This is the daughter we believe to be named Linda Pierce Jones or Linda Martin Jones. We believe she (as well as the other two children) were born in Harris County, TX, tho we are not sure. This daughter, Linda, was "given" to Pat and Bruce Pierce (or Pearce?). They were NOT related to Mildred, but rather were the owners of the bar where she hung out called Pat & Bruces (original name, huh?. I have visions of "Here. I'll trade you this baby for a long-neck BUD!" Ha!) Anyway, this bar was located in the Houston area. We believe Mildred's mother's name may have been Louise (at least that was what she was called) Daniels and that she also married several times. Mildred's siblings were named Jimmy, Jerry, David, Anita (married Bill Bisker or Visker), Doris (married Ted Bosworth) & Curtis. We have heard that Mildred later moved to the Dallas area and that she is in fact deceased, many years ago. The daughter whose obit we found died May 5, 2011 and was named Jamie Yvonne Koepke. Tho she was NOT the child of Michelle's father, Floyd Donald Koepke, perhaps Mildred had kept his name. Jamie Yvonne died in Omaha, Nebraska -- but it shows her home as being in Livingston, Louisiana. She was born in 1963, so was younger than Michelle. It was a very short obit, showing no info for survivors. However, an online tribute did mention something about "the kids" missing her -- so she possibly had children. We feel it is our best bet to concentrate on trying to find Linda Pierce (or Martin) Jones in Tyler, TX. Again, she would be 53-59 years old, we think. Not only did she hire a private investigator several years ago to try to find all her half-siblings (meaning she is smart) but she also obviously cares. When the investigator called Michelle's dad years ago (5 to 10) he lied and said he didn't know where his daughter was -- because Michelle had not been told the truth about her birth. In fact, Michelle was living next door and still does here in western NC. An interesting side note: Michelle has always been very artistic. Got in trouble in high school for drawing pictures on her homework and tests. She went to college and studied commercial art. Her dad told her yesterday that both Mildred (her birth mother) and her birth grandmother were artists and worked for a company doing fashion illustration in Houston for newspaper advertisements. Now she knows where she gets her artistic ability! Thank you so much for any help anyone can give!