looking for lost sisters born in july and december mid 70's

I am looking for two girls who were adopted out of my family in the mid to late 70's i believe. I know there names are melissa and regina. melissa is older and they are about 18 months apart, i believe. They were about 2 or 3 when they were adopted. These girls are my sister's and I would really like to find them. If you have any info let me know. thanks!