Hmm, I am also new around here, and most of what you have written looks ok to me (I have never used windows remote desktop, but I have used VNC before, on both linux and windows machines, remotely).

The one thing that looks wrong- you said that you opened the port and assigned you PUBLIC IP to it - that should be your PRIVATE IP - ie, the local ip of the computer you wish to connect to (also - this computer should have a static ip on your network, or it will get messed up).

Then, in the client on your N810, use your PUBLIC IP, and the correct port, and it should work. The only problem then is keeping track of your public IP as it changes - I personally use DynDNS b/c it is free and my router has the software needed to update it built in.

If you already used the proper IP and simply made a typo, the only other thing I can think of is check that the port is correct, other than that I have no idea.

Patrick