Regarding an MBA, there are an increasing (though, AFAIK, still small) number of programs that focus on preparation for a career in the nonprofit sector. If that's the kind of work you'd find rewarding, shopping for an appropriate MBA program might be worthwhile.
A statistics master's doesn't sound like a bad suggestion, whether as a terminal degree or as preparation for continuing on to an economics Ph.D. (I'm considering the same thing.) Your low grades in calc I/II and lack of multivariate calc (I'm assuming) are minuses but probably not deal-breakers at many schools.
I do think you could find a home at some economics Ph.D. program with your profile as it is but, as you probably realize, not a terribly competitive one. Just adding A's in Calc III and Real Analysis would be a big boost. One of the advantages of doing so in the context of an economics program would be the chance to get a good
LOR from a econ professor.