Do you use a computer with your daughter? If there are learning as well as attentional issues, kids are often much more willing to do the kind of practice that is necessary to succeed when they are working on a computer rather than with flash cards or doing tedious written drills. There are other ways a computer can be used to maintain interest and increase learning. For example, there's a wonderful computer program called Inspiration (Go to http://www.inspiration.com for a free 30-day download) that is particularly good for jump-starting the writing process. Multimedia CD-ROMs can make history and science come alive for all kids.
Have you tried linking up with other parents who are homeschooling kids your daughter's age? Well-structured, cooperative learning activities with other kids can also help maintain focus. An excellent resource for kid-tested activities is Sandra Rief's How to Reach and Teach ADD/ADHD Children. She also has a video available to see some of her strategies in action.
You might also try to attend your local CHADD (Children and Adults with Attention Deficit Disorders) meetings to hook up with other parents who may be experiencing the same difficulties. Call CHADD's toll-free number 1-800-233-4050 or look at their website to find out if there is a branch in your community.