Steve, The best thing I can tell you to do is to try and get a copy of you're mother's birth certificate. Then try to find her parents in the census. You won't find her, since the only census years open to public go to 1930.
I don't know if you have a NARA location near you. It's the National Archive Administration and they have all the censuses for you to go through free of charge. I think their site is NARA.org. If not, do a search and you'll find it.
My Madores go to the 1900's but it was my gg-grandmother Rosa. She was one of 12 children so you could be related to one of them or to another line. Her parents were in the Fort Kent area of Northern Maine but it's possible your grandparents migrated from that area too. Please contact me if you get the names and I'll see if I have any matches or if I can be of any other assistance. A lot of people have helped me in my search and it's nice to return the favor.