Adoptivemother ISO birthmother in Cedar Rapids

We know a lot about the birth mother, but have not been able to exactly find her.The agency that we adopted thru acts like there is nothing that they can do for us other than forwarding the letters and pictures that we take there but they tend to black things out on the letters....and they are non identifiying things... Our son was born 8/8/02 in St. Lukes Hospital in Cedar Rapids, IA. Birth mom is Robin.