Calculate limiting molar conductivity of BaCl2
I'll answer the second part of your question first: you have one equation with three unknowns, so you need the value's of two more unknowns, namely the molar conductivities of Ca++ and Cl-.  They are readily available from the CRC Handbook of Chemistry and Physics.  Every chemist and chemistry prof and library has one.  You could also find those values from online resources, just be sure to check with reliable sources.  An internet search will turn up many.  Once you have those two values you just plug them in to your equation and you are done.  You are correct with your V values.