Just a question- why do an MBA right now? Maybe you should just get back to work instead. As Neha has pointed out, any b-school you apply to will want to know why you need that second MBA and I think saying that it will help you in getting back to work after a year long break does not sound a very convincing reason.
You should aim for a score above 700, the higher the better. As you do not have any quant background, think of it as a requirement to score well on the GMAT with a high quant score. Many of the MBA foundation courses are analytical and unless you can prove it to the adcom that you will cope well in class, its going to be a tough fight. Consider taking up a few quant based courses online. One thought is that you spend another 1-2 years to beef up your profile (which entails getting back to work) and then do an MBA if you still need it.
Among your b-school choices, INSEAD prefers candidates who have international work experience/ exposure - apply there only if you meet that criteria.
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