I'm new to this community as well, but have some experience with the home networking topic. I have an old computer that I use to serve web pages and can ssh into. It has only one network interface. I'll try to explain how I set this up.
1) You need to find a way to locate your network from the outside world. At first I had a dynamic IP from my internet provider, but my Belkin router has a feature that links a domain name to the dynamically assigned IP via dyndns.com. You just create a domain name (i.e. something.dyndns.com) and the router will push updates to dyndns.com, telling it what your dynamic IP is at that moment. You should look in your router's configuration and see if that's possible. If not, call your cable provider and purchase a static IP address. I use comcast and they just made me switch to a "business" plan and charged me $5/mo more.
2) Forward tcp requests on port 80 and 22 to your server's internal IP address. Your router likely gives each computer in your network a dynamic IP. While you can assign static IP addresses within your network, it will be easier at first to just use ifconfig to see what the server's IP address is. So go into your router's config page and forward those ports to the server's IP. (FYI it's not very secure to use default ports for outward facing servers ... eventually you'll want to configure your server to use some higher ports). Hopefully if your router can do this, you shouldn't have to mess with iptables at all!!
3) Now that packets are getting to the right destination (your server), you need server software. Install apache (or glassfish) for the web server, and install openssh-server. Your apache works if the web browser shows "IT WORKS!". After that you can put your html in /var/www/.
These steps assume you have a fairly recent router, and that you don't want your server to act as a firewall/router. If you want your server to act as a router, you'll need two network interfaces (I'm trying to do this now, with not much success!).
Those steps are pretty vague and have no actual commands because I don't know what distribution you plan to use. If there are problems please follow up.