looking for birth sister

I am looking for my birth sister Debra Lyn Beck born 4-28-54. We beleive she was born in Colorado, or maybe Wyoming. There are 6 of us all together. In 2002 I was lucky enough to find 4 of my brothers but we can not find our sister. Both birth parents are deceased. 2 brothers live in California, 1 brother in Nebraska, 1 brother in Colorado and 1 sister in Colorado. We are at a stand still and don't know which way to ture at this point. If anyone has any information about Debra we would be very grateful.