There really isn't a whole lot out there that isn't a trial version (and most trials don't export to the .3ds format you need for NL). The only thing I can recommend is upgrading your OS to something a bit more modern, and then use sketchup's pro trial. It's an 8-hour trial, but I
think you can use it indefinitely as long as you don't quit the program, but that's just what happened to me.
But if you don't want to upgrade, I think Blender is your only option.
http://www.blender.org/download/get-blender/