D.,
I am so proud of you that you are not embarrassed to discuss your daughter's 'attitude problem!' As a mother of an older child, been there, done it, wrote the book!!!
Do everything possible you can do to stop her thinking that it is perfectly ok to disrespect everyone in the home. If you don't you will have about 9 more years of craziness to deal with.
It is important to be consistent with her and set boundaries. If she continues to speak to you are her siblings disrespectfully, she will no longer enjoy all of the gadgets (cell phone, computer, phone, etc.) until she learns how to speak kindly and do as she is told.
Don't freak out and worry that she won't like you. They love us to death, but they just have to see how far they can push. If you allow them to push, you end up losing! You will be spending day and night dealing with her until she leaves for college.
I now hear from my child, that even though I was a great mom, I let to much go by and that's why he hurt me the way he did, because he could!!!
Stay strong and lose the guilt of being a single mom. There are a lot of us that were and still are single moms. You can do this just be direct and non emmotional! Yeah right!!! A non emmotional mother...
Good Luck!
L. Hein
Author
THE BOOK "I'm Doing The Best I Can!" (They won't always be cute and adorable)
www.lisarhein.com