OPEN DNS and standalone wireless netwrk

I use OpenDNS at home and find it excellent. I would like to use it at our church where we provide a secure wifi network and would like to be able to protect the users from the "dark side" of the internet.   We operate the system with a wirless ADSL modem sat on the phone line and normally no PC is physically connected to it, and our ISP provides us with a dynamic IP address. Herein lies the problem. The IP address can change at any time, yet OpenDNS uses the IP address to know what your filter requirments are, unknown (or new) IP address equals no filter.

At home I run a dynamic IP monitor on my PC (which has an ethernet connection to the modem) so that any changes to the IP address are broadcast to OpenDNS and so my filter requirements are recognised.

But with no "permanent" PC connected at our church, how do I get OpenDNS to learn our new IP address.

Alternatively does anybody know of any other way to provide parental control on a wireless network that doesn't rely on a PC connected to it?