Jez:
I'm involved in children's ministry at my church and there are numerous books, videos, games, etc that you could purchase and use to study with your daughter. Check out your local christian book store - you'll be amazed at what great stuff they have.
The biggest advice I can give you is to make it a positive and fun time spent with your daughter. If your study time is boring to her (like the meetings and traditional JW family study) she'll just tune it out. However, if you can capture her attention she'll actually remember more of what YOU had to say than what she hears at meetings or through her dad. Kids LOVE to learn about Jesus but are rather bored with general doctrinal issues. So - if you can show her what's wrong with a JW doctrine through a Jesus story that might capture her attention.
Here's an example: I read a few short scriptures to my daughter where Jesus touched and healed a leper. Then I told her about the story where Jesus healed a young boy in another town - he didn't even see the boy, let alone touch him, and he was healed. So I asked her "why do you suppose Jesus made a special effort to TOUCH the lepers?" We talked a bit about what leprosy was, how it made those people outcasts, etc. Then applied that to today - who are the "lepers of today? and "how could we reach out to touch them?" You could go a bit further with this one by asking your daughter "if someone really needed help and love, but they didn't believe in your religion - do you think Jesus would still want us to reach out and touch them like he did the lepers?
Here's a site with some good ideas - I use this one a lot for inspiration: http://www.kidssundayschool.com. Check out the games and the lessons links.
It is imperative that you counteract the mind controlling tactics of your husband. And I agree with other's comments to teach her to think for herself and not to be afraid to ask questions - even questions such as "is there really a God" and evolution questions. Allow her to really consider all the possibilities - she'll trust you more and open up to you more.