Try to find out from someone else in the extended family, who may know more about where the Russells originated from - it is a fairly common and widespread name.
I'm assuming that you feel they came from Britain originally - if not, where do you think they came from? There may be immigration / emigration records to find.
Do you have the dates of birth of all the brothers of your father - from free B M D you might that way discover the mother's name, and / or the area in Britain you are seeking.
From the information of your father's marriage certificate and marriage certificate, can you discover the names of parent(s), that may help you.
Good luck with your search.