Honestly.... 50% hard work for little pay/volunteer work and 50% luck in finding a good enough position in a related field. Most people I have talked to, myself included, started out volunteering in their field years before they wanted to get in, and showed a continued and varied commitment to finding work (volunteer and paid) in the health field before applying. Taking a year off might work out in your favour, but it could also lead to a frustrating 6 month job search and an unimpressive 6 month job or unpaid volunteer position.
In your position, I would probably try and find volunteer work in your field as soon as possible, and work on your job connections through volunteering. Then start applying for jobs, and see if you get any... you could also accept the offer to the school you did get into and then only take a few courses that are required in all MPH programs (Biostats, or Into to public health... something like that) which you could use as transfer credits and as a way to boost your application to your preferred program next year.
Good luck!