Usability Question (not exactly code related)

I'm developing a system that is [basically] composed of three components: Server, Host Client [HC], and a Normal Client [NC].

Server proggy is running on my own server. The HC and NC are distributed to users.

What I want is this:
HC alerts the server of the HC's presence. A NC connects to the server looking for an HC. Server responds with info about the HC. HC then passes data to the NC.

What I have is the HC connects to the server, broadcasts its presence, and disconnects (the server stores the HC's IP addy). A NC connects to the server, receives the HC's IP, and connects. Now, this method requires the HC's firewall and router to forward the right port.

My question is this: do most everyday users know enough to understand how to forward ports for BOTH firewalls AND routers?

I know I could have the HC keep the connection with the server, and have the NC connect to the server, and do the data exchange this way: HC -> Server -> NC, instead of just HC -> NC, but that would absolutely overload my connection because of the number of users I'm hoping the system to get. I've been thinking about purchasing a dedicated server somewhere, but I don't want to do that until I know I'll make enough money from this project to cover those expenses.

Thoughts anyone? (Especially those of you who know what you're talking about)