I'm sort if in a similar boat as you. To clarify:
Not a strong econ background, mostly pure math.
Same with GRE.
University of Chicago's direct affiliate has a Master in Public Policy. Here's the link: http://harris.uchicago.edu/academics/programs-degrees/degrees/master-public-policy-mpp?gclid=Cj0KCQjw1JbPBRCrARIsAOKj2PkLUDMmdUlcNYqHxrNkaLD95sKC8fa1PDk7ll5jWVeaBcK-UBdrZJEaAuKQEALw_wcB
On the other hand, there's a program for Analysis and Public Policy by Paris School of Economics. I'm very interested in applying for that. Only hurdle is, I don't know how good the university is. But I can say that there are alums who've gone on to work for OECD in the policy sector.
Hope it helps. All the best.