Perhaps an ASCII picture of your layout would be handy.
In my case, my WiFi Access Point is a device connected to my OpenBSD router. If I understand what you've written, your WiFi access point is your ISP's router, and the only OpenBSD platform is your laptop? If so, then the only encryption available to you directly is WEP. If you have a second OpenBSD platform, it could be used to route encrypted traffic.
My environment:
Code:
WiFi AP
|
{internet} -- [OpenBSD] -- {wired LAN}
A possible configuration you might be able to employ, if you have two OpenBSD systems. In this case, you can't use authpf; WEP would have to be used to control access; but improved encryption could be had by tunnelling via SSH:
Code:
{internet} -- [ISP's WiFi AP] -- {wired LAN} -- {2nd OpenBSD box}
You'd set up an SSH session between your laptop and the 2nd box, and use SSH's SOCKS proxy to provide more robust encryption.