when you buy a cuecore you get the power supply, the only thing you may need to buy is a 5 to 3 pin adaptator if you use usually 3 pin xlr for dmx...
And the cuecable is not absolete, cuelux and cuelux pro are just 2 different softwares, with 2 differents aims. You will always be able to use cuelux with your cuecable as cuelux do not work with a cuecore!