I've got a similar setup, the only difference being that I have one of those all-in-one Netgear devices (Router, Firewall, Wifi AP, Modem). My SME works quite happily in this setup (server-only mode), so in theory I don't see why you would have a problem with your Linksys AP.
Instead of forwarding individual ports to my SME box, I just setup a DMZ rule in my Netgear Firewall. Ergo, every port that I don't have a rule against, goes to my SME box. This is really not a good idea if you are concerned about security, a better approach would be to forward just the ports you need and ignore the rest (I am just being lazy).
Back to your problem, is your home IP 68.36.174.236? If not, then that's what the name servers think it is. If this is correct, and you still don't see your domain externally, did you make sure to setup the domain on your server?
Good Luck