Mere accumulation of degrees cannot develop a career. You need to put on use whatever learning you have made in your management course (MPM). Have you done that? Person grows by implementation of learning. Therefore, I recommend you concentrating on that.
I doubt you have made a proper career plan. Acquisition of some degree should be part of your career plan. Therefore, first make a career plan till 2020. Identify the competencies required for the future positions and try to acquire them. This is far more difficult than adding one more degree.
Anyway, to answer your query, I can say that you may do LLB. Thereafter, you can pursue career in Industrial Relations (IR). Again it depends on your like and dislike and interests too.
All the best!