I couldn't follow the link to see what the modules were, but if they were like the FS1000A/XY-MK-5V ones I got, upping the voltage definitely helps, with a caveat.
In my experience, it didn't do any good going using the voltage through one of the Arduino pins (e.g., Vin). Running it just off the Arduino at 5V (via USB), I would get a range of about 6ft/2m. If I plugged a 9volt battery into the Arduino and still fed the transmitter via Vin, there was no improvement in range. If I powered the transmitter directly from the 9v battery, the range increased to more than 30 feet/10m.
Bob