I would begin by beginning to give all 3 kids daily chores that must be done by each child (on their age level). I say all three - this way she won't feel singled out when the chores are enforced.
Each child can begin by cleaning their own space (bedroom) by putting away toys, books, papers, dirty clothes, etc. Each child is old enough to make their own bed.
If the child does a chore badly - make her/him do it over until it meets your standard of what's acceptable to you.
As far as the "talking back" - be firm with her about the fact it will not be tolerated. Tell her if she does it again then she will be punished/disciplined (grounded or whatever you feel is appropriate). Do NOT back down. Don't keep threatening her 10-15 times. Follow through the very next time she back talks.
Also, for this to work you must be consistent with your punishment. Consistency is the key.
You can't be consistent for a week then back off - it will work against you.
As far as telling others what to do - remind her that you are the parent and that its NOT her job to tell other people what to do.
Remind her that she is acting bossy and that its not a very good way to make friends. Being bossy will actually drive her friends away after a while because they will get tired of being treated that way. They will find new friends that are more pleasant to be around.
Encourage her with some activity that she can do by herself; such as reading a book. This will help her learn that she can be by herself and still have fun.
My 24 year old daughter was the type that occupied herself when she played and did not require someone to always entertain her.
She spent many hours reading, playing with toys by herself and such.
Your daughter sounds like she always wants to be the center of attention. She has to learn that she has to share - even time in the spotlight with her siblings. Don't give in to this because if you do - you will create a monster of a child.