Urgent help needed : Mapping IP on local PC to another local IP

I'm demoing my game at PAX on a PC and have a build of my game that connects to the local multiplayer server with an ip of 192.168.1.10. The problem is now that I'm in another country and have connected with mobile tethering, so the IP of the local multiplayer server has changed to 192.168.42.39 and the multiplayer server software has thus changed this.

Is there any way I can route any connections to 192.168.1.10 to point to this new IP?

I tried setting a hosts file entry to 192.168.1.10 localhost, hoping that would work but it doesnt.

Any ideas? Please this is quite urgent I cant demo my game if I dont get this sorted :(