I would create a kids account, and your account.
Add that to the kids account, and not to your account.
I can not really comment on this too much beacuse I am a kid, but I have heard good things about NetNanny.
http://www.pcmag.com/article2/0,2817,2255002,00.asp http://www.netnanny.com/products/home
The first link is a review.
The second link you can buy it, or download it and try it to see if you like it.
Good luck!