What do you mean by range in this case? If you mean how far apart they are, I have only tested everything within the same room, connected to different mains outlets.
In my case I tested inside the room , it didn't go that far(only to the nearest socket) , what's the schematic you made (As in something close to the Data sheet which NXP have provided or something else ?) and the code you uploaded (I used the Radio head library what did you use )? I'm planning to do this as my final year project in my university hope you'll be able to help with it .