The Ultimaker 2 comes with Cura software for the G code, that takes an STL file and works OK.
I'd like the dual extruder option now, got fed up of messy undercuts or trimming loads of support parent material away. There is a dual extruder kit available for the Ultimaker 2 from an Italian Ultimaker reseller for about 250 euros, I may try that since nothing is forthcoming from Ultimaker yet.