Dear Saraswati, Mere accumulation of degrees cannot develop a career. You need to put to use whatever learning you have gained in your management course (MPM). Have you done that? A person grows by implementing learning. Therefore, I recommend you concentrate on that.
Career Planning
I doubt you have made a proper career plan. The acquisition of some degrees should be part of your career plan. Therefore, first, make a career plan until 2020. Identify the competencies required for future positions and try to acquire them. This is far more challenging than adding one more degree.
Further Studies Recommendation
Anyway, to answer your query, I suggest you consider pursuing LLB. Thereafter, you can pursue a career in Industrial Relations (IR). However, it depends on your likes, dislikes, and interests as well.
All the best!
Regards, Dinesh Divekar