Some one else had a similar post, recently, and I suggested to them that if you want to get a good job in the research field, it might not be a bad idea to retake your examinations and improve your score.  If you would be willing to do the work, it could greatly enhance your chances of having the job your really want.   What can you lose by continuing to improve yourself?  The competition is great, and the jobs are not too numerous.  If you do not wish to retake those exams; then perhaps it is time to change your area of interest.  It has been several years and if you cannot find the kind of work that you hope to do, it is time to access your potential, and make a change that works best for you.