Get Hamachi mate. Here is the link https://secure.logmein.com/products/.../download.aspx. You both want the unmanaged version. You also both want to untick move matches for TV and you need to run as server. If your running as server just create a new thing on Hamachi and then a password. Your mate then copies the new thing and then it should ask for a password and you give him that then you should be able to play. I dont know if you have to start a new game or not and when your mate joins. Im not sure if I have explained everything as my mate joined the game and I was the server.