well first, VLC doesn't yet support AMR audio, because there is no Free and Open Source implementation of the codecs, only the official reference codec, which falls under the copyright of the 3GPP governing body of these codecs.
second, any number of methods can be used for remote activation, but basically i would just launch VLC on the server with the http web interface (vlc -I http) and then from the windows machine you can call the correct url and vlc will start playling. (see
http://servername:8080/ after launching vlc to get a webinterface. If you look at the pagesource you will easily understand how to construct your URL's for remote controling).