So to help this out we're going to pick up a pair of new shoe inserts. They're similar to the ones she currently uses but in addition to supporting the arch of the foot, they come up around the back of the ankle to give it additional support as well. Unlike an ankle brace, they don't immobilize the joint, so she'll still need to strengthen those muscles over time. Then we'll get a little pair of high top shoes to help as well.
To strengthen my daughter's hips, we've been trying some new walking exercises. Instead of using her walker, we've started making her walk hanging on to a towel held horizontally in front of her a little above waist level. She can hang on for balance, but unlike the walker it won't support all her weight. This forces her to bear her own weight instead. So far the little one tires pretty quickly, but her strength will build gradually and hopefully with it more confidence in her hips and ankles.