192.168.X.X IP addresses are only used within a private (internal) network. You have to use your public IP address instead if you want to access your media outside of your network. You'll have to also make sure you've got the port forwarded correctly as well or else it will not work.
You can get your public IP address here:
https://www.whatismyip.com/If you have a dynamic IP address, you'll have to update it in JRemote every time it changes (e.g. when connection drops and reconnects, modem/router reboots, etc.). If you have a static IP address, it shouldn't change.
And the correct port (unless you've changed it or are using SSL) should be 52199.