Can't connect to host.

Likely a firewall blocking the server's SVN port. You'll need to track down what port you're using and then make sure:

 
1. the chosen/configured port does not conflict with other services (that might get started before it) 
2. the firewall is enabling remote connection. 

My knowledge of Windows is stale but "netstat" is a Unix/Linux tool. Not sure what it does on Windows. On Linux I'd likely check the ports in use using "netstat -ant" and look for "LISTEN". Hope this helps.

Your router is acting as a NAT. You’ll have to setup a DMZ if you want to connect from the internet. Probably not a good idea since it sounds like your background is a bit “light” and it’s easy to get into trouble (exposing anything to the internet means you’ve got to do a LOT of IT continually).