Instantiated Game Object is at the wrong location.

All of the objects are getting instantiated at the pivot point instead of the centre point. As you can see for some reason, my procedurally generated mesh's pivot point is located at 0,0,0 instead of its centre, which creates a few problems for my position calculations for other objects, including instantiating new ones.

So as for the question to fix this problem: is it possible to change pivot point to its mesh's centre point? (some googling shown me that it might be impossible) or is it possible to get the vector for the mesh's centre point, so that I could instantiate objects at that vector?