Even I worked with students 2/3 times a week, my students need more practice at home.
I usually ask them to practice more at home to enhance their skill.
For language practice, http://www.bussu.com helped my students.
They have free section and it is pretty good for beginners.
Paid section is even better for advanced students.
For elementary math students, I use http://www.nekopy.com.
Which is developed by Japanese school teachers and it is very useful to improving basic calc. skill with animation and fun games.
I will update when I find more useful sites for tutoring.