Books that I love that have a strong female lead:
"The Paper bag Princess"
"Pippi Longstocking"
"Ms. Rumphius"
The enchanted forest chronicles (this was my FAVORITE as a kid)
The dark materials series - might not be age appropriate yet
The Harry Potter series (Hermione is a rockstar)
Here is a list of children's books that have a focus on self-esteem:
http://www.amazon.com/s?ie=UTF8&keywords=Self-esteem&...
I also would love to recommend getting/making a feelings chart that lives in prominent place. I have made some with my little ones (2 and 3) and it's both fun and helpful. I also like games like: lets do angry faces, let's do sad faces, let's do excited face, let's do proud face, etc.
The best thing I think we can do, and that you pointed out (awesome, mom!), is to be what we want our children to see; be what we want our children to be. So, if you are noticing patterns in yourself (again, really awesome that you are looking, seeing and going to work on this!), take steps to work on self love, acceptance, confidence and esteem. You deserve it and your children will benefit from the work you do.
One very simple action is to write an affirmation above every mirror in your house. Cheesy, I know. But it actually works.
"I am beautiful, inside and out"
"I am love, I am loved, I love"
"I love myself"
etc.
Good luck! You are brave for broaching this and I commend you! Your girls are lucky to have a mama like you!
ETA: I just thought of one other thing. Most of Hayao Miyazaki's movies
(Nausicaä of the Valley of the Wind,
Castle in the Sky,
My Neighbor Totoro,
Kiki's Delivery Service,
Porco Rosso,
Princess Mononoke,
Spirited Away,
Howl's Moving Castle,
Ponyo)
have incredibly strong, courageous female leads. They are amazing films and I feel they have an incredibly positive message.