In my house I have cable broadband so:
cable modem -> linksys router -> network/switch -> radiora repeater
First thing to do is give your radiora repeater a fixed IP address. The next thing to do is login to your router and setup port forwarding received on port 23 to the ip address of your radiora repeater.
Now, visit a site like http://whatsmyip.org
to view your current ip address.
telnet into the address displayed and if setup correctly you should be able to telnet into your RA repeater.
Now, if your like most people (myself included) you do not have a static IP address (your ip address changes all the time). So, hard coding your IP address in your remote control system will only work until your ISP changes your IP address.
Follow the instructions in this article
to setup a dynamic DNS account. (free, this will correlate your current IP address to a URL that doesn't change like myhouse.dyndns.org)
Once setup, you should be able to telnet to myhouse.dyndns.org (or whatever your assigned URL is) to get into your repeater.
That's for remote 3rd party control.
I have not tried to remotely update my repeater however I'm sure you could. Manipulate the windows host file
and port forwarding on the router?