Getting target level from 3D world

[Skipolav]

I have a macro set up to cast the appropriate rank of a spell based on the level of my target. If I don't have a target, the script falls through all of the if...then...elseif statements and puts rank 1 on the cursor. It'll cast that rank 1 spell when I click on someone in the 3D world, even if they are capable of recieving a higher rank.

I can check to see if there is a target and cast normally if there is one. But if there isn't a target, how do I tell it to wait until a target is clicked and get that target's level?