"Within a year" is a hefty constraint to meet for a good technical degree, given that your plan seems to include part time work. May be think about a MS rather than one year certificate thing.
Your background is a hot sale. Statistics is one of the hotter subjects and has a wide range of application in US. With a good knowledge of applied statistics, you could have a good career in fields like Public Health, Medical Informatics (a grand challenge for this century) or any other field requiring design of experiments or probabilistic modeling. But again, Stats in itself is too broad.
I would suggest to screen some job vacancies and college programs. Try to get a feel for what are companies looking for and what is offered in your area unis. Then, try to methodically rank things you think you will enjoy most and can visualize doing after couple of years. Hopefully, your ranking will boil down into a handful of specializations in a couple of iterations. After the process, you should be in a better position to answer the question than anyone else.
Good Luck!
