How do I monitor data usage? and what do I do to protect my computer/network?
Is there any way I can add security to my computer?
Well, this is why I advised against doing it this way. First of all, is your network wpa encrypted? (I'm not sure if this affects incoming data on an open port, though, but it should be encrypted anyway) For usage, try going to a terminal and typing "httpd status". I'm not sure how to do that via GUI as I haven't done a whole lot with apache. (You did say it was apache, right?)
Firewalls are a great way to have security, but you did just basically poke a hole through one of the ports. Also, I'm hoping you don't use this computer for anything else, and never turn it off. (One of the many other reasons you shouldn't directly host this)