Ok, is this your setup?
Webserver(192.168.x.x) connected to router that has one public IP
router forwards port 80 to 192.168.x.x
your saying from the internet if you goto your public IP, you get the router config page, not the webserver?
If so, put the webserver on a different port and try it, see if that works. Or, bypass the router and try accessing it and see what you get.