You might want to try going to no-ip.com and setup a free account and use a redirect to a different port. If it is a linksys router you can't use port 8080 either(it is used by the router).
Then you need to go to /etc/httpd/conf/http2.conf
look for these lines
#BindAddress *
<IfDefine APACHEPROXIED>
Listen 8080
</IfDefine>
<IfDefine !APACHEPROXIED>
Listen 80
</IfDefine>
Change 8080 and 80 to the port you decided to use, I used to use port 12300
That should get you going.
I have used Mandrake for over a year as a server, if you want you can e-mail me directly and I'll try to help more.