Well, I would contend that theories do not become laws. Theories and laws are different kinds of things. Theories are explanatory, whereas laws are simply descriptive. A law says, "here is a model or mathematical formula that predicts the behavior of this system," whereas a theory says, "here is a mechanism that causes this behavior" You can, and do, for instance, have both laws and theories of gravity, and they are separate and not genetically related.
I do agree, however, that hypotheses can become theories through elaboration, extension and testing. (In that case one might distinquish between explanatory hypotheses, which may become theories, and descriptive or generalizing hypotheses, which may become laws.)