Trust me, you MUST have a router.
As a temporary fix, if your Windows computer also has a wired network adapter, you could run a network cable from it over to the Mac, enable ICS on your wireless network adapter, and your computer will now share its wireless connection w/ the Mac.http://support.microsoft.com/kb/306126
In effect, you’re using your computer as a router. Of course, only you know if that’s practical. And this is only a temporary fix. You should get a good standalone wireless router (or wired-only router and patch the Netgear WAP to it, works the same). Even if you only had ONE computer I would recommend a router since it provides great protection from Internet threats.