Home web server on Netopia 3347

I have a netopia wirelss modem/router and I want to get a home server going on it. I presume a fair few people have these as it came with eircom broadband. I have LAMP set up and working fine, full access to my site through http://localhost/. I want to configure the router so that my server can be accessed over the net.

Here is the documentation for setting up port forwarding on the netopia 3347 http://www.netopia.com/support/intl/eircom/technotes/IEQG_025.html

In step 4, I put 80 in as the base host port but I am unsure of what to put in the global port range?

And if I follow this guide I still can't see how this could work as there are three laptops using this wireless router and I don't see anything in those instructions about specifying the computer to direct the request to. So a requst comes in on port 80 but how to I make it go to my laptop?

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