Searching for my birthmom

I was born in Subiaco, Perth, in WA May 7th 1973. I was given up for adoption just after I was born. I came to my family when I was about six weeks old. When I was 18 months, my family moved back to Norway were they came from and we have been living here since.All I know about my birth mom, is that she had Polish parents, 2 sisters and 2 brothers and she was quite young, my guess is that she was between 16-18 when she got pregnant.