At the end of the manual you can see the Robonova-1 is built for expansion. It already has the following options listed in the programming manual:
Looking at the Hitec Robotics website it has the following:
Speech synthesis module
Remote Control transmitters and receivers
7.4V Lithium Polymer battery (6V regulated) instead of the standard Ni-Hm. I have some of these available and would give longer running times and are a lot lighter, at the moment there isn't an issue running the standard batteries.
HSR-5995TG robotics servo 24Kg/cm 0.12 secs for 60 degrees. These would make the Robonova almost perfect more than doubling the power it has.
The first addon I need to get is some type or wireless controller, either using 433MHz RF or bluetooth. There is a discussion on the Robosavvy forum about bluetooth and will see where this goes.