There's the old and trusted way of using Net User which allows parents to set 'time limits' on the use of a PC entirely. Assuming these PCs have individual "Limnited" accounts for the children but an Administrator account, (password controlled), for you, you can use the Net User command to lock them out of their PCs for set periods.
More about that here; http://en.kioskea.net/faq/2228-set-a-time-limit-for-the-use-of-a-pc
The other way may be better. But it means discussing with your neighbor. May be a suggestion or similar that you noticed from your own wireless capable computer that their wireless connection is unprotected, and do they need help to change the security to WPA-2 with a strong password? That would stop unauthorised access.
I have setup live parental controls on my Netgear 3400 router,and it works just great. I have 2 teens that after lights out can access neighbors internet signal that has no security...kinda defeats what im trying to do....anyway to block the neighbors network from the kids laptops ?....both are windows ....