That girl is Katya, she joined after Nastya left the group. I remember Nastya had brown hair.
The girl next to Olga in this picture is Nastya:
http://t3.gstatic.com/images?q=tbn:A...WIwFTreWA8R1LN
I used to have more photos of them but I lost them when my computer crashed
. That's why I was wondering if anyone else has them.