So if I understand correctly, you have a Steam license, but want to make the free, stand-alone version (presumably downloaded from here) into a full licensed version?
That is not possible. The steam license and the license from this site are 2 entirely different licenses. Steam handle their own licensing and Scirra handle the stand-alone version. Buying one does not mean you get the other, I'm sorry to say.
Is that what you were asking?