Either of those schools would be good choices and a 560 GMAT score should make you relatively competitive at both. Admission of course would depend on other factors - how much work experience do you have?

Exeter's One Planet MBA is also pretty well regarded in this area, you might want to check that out.

This isn't a typical career path for many MBAs, but those schools are particularly good in the niche. I'm not sure how lucrative that career path is, but you might want to make sure you'll have decent ROI. Another approach would be do look for a general MBA at a higher tier school - maybe you'd need a better GMAT for this - and then just take CSR classes as part of the program. This way you'd keep your options open after graduation.

I think the average GMAT at Sawyer tends to be in the 550 range so you'd probably be fine.

Was the GMAT examine difficult? I am a blogger and want to apply for MBA and want to take classes for GMAT.

It's not so much the GMAT's 'difficulty' level but a test-taker's ability to target their weaknesses and focus on prep. For most everybody who has completed high school, you should understand the concepts. Many are rusty on specific areas (the quant, for instance), and takers who aren't 100% comfortable in English might struggle with some vocabulary. Nothing some targeted test prep can't fix though!