Troubles with a small home router [r/o]

I have a broadband cable account
and I would like to set up a very
small website. (limited amount of
users so bandwith doesn’t go
kapoof!) I am using Mac OS X with
the Apache web server built in. So
everything works good except for the
fact that the computer goes through
a gateway router. And I can’t remove
it either. The page works fine on the
LAN, but that is just the standard
192.168.0.x router assigned
numbering configuration. So, how
would I access the site from outside
the LAN? Let me know if somthing
here is unclear. Thanks