Your question was hard to follow. Are you going to continue to have your daughters go to public school and you also want to add to their schooling experience? Or are you exclusively going to start home schooling? The answer to this question should dramatically change any answers you receive.
For your younger child, Starfall.com is a great and high interest reading website. There is also a website called Mathletics. You have to pay to get access (our school paid for an account for each child). It is good for math practice. There is also a spelling website that has ties to the math one. We have not used this one yet but I am considering paying for it.
I know that there are many homebased websites that provide full curriculums for each grade level. If you google Home schooling, I am sure that they will show up. You can also talk to your school district office about their home schooling options. They can probably connect you with a group.
If you are just adding to their education but keeping them in a traditional classroom, consider adding to their education by taking them to museums and other learning experiences such as art lessons that seem to be disappearing from the public school scene. The public schools in my area, do not have P.E. in the younger grades. If we did not attend our private school that does have p.e. I would definitely add sports to their afternoons.
Please continue to read to both girls. Even your older one needs to hear you read. You can give her access to harder concepts by reading to her even if she is above grade level.
When we come home from school, we immediately tackle homework after a light snack. I find if I let them play first, it is a larger struggle to get them back to the table. Each girl should be able to do their homework by themselves at this point so you can make dinner and then you should take some time to go over their answers.
Good luck, I am an educator that never really understood how hard parents have it until I was a parent. I am now completely against homework because there is so much more meaningful activities you can give your child. But of course, you have to have the resources to provide all these extra things. Frusterating to want to give your kids so much.........