Thank you for posting your story and welcome to GMAT Club!
1. Why the Jan intake schools besides waiting?
It does limit your options and also makes it a bit more tricky with job search since you most likely will graduate in the Fall/Winter. Not necessarily bad as you may land the job you may otherwise wait for half a year but most internships and MBA-related positions are usually recruited in a certain pattern of months
2. Where do you want to work/be/stay?
Are you coming back to Brazil after graduation? If not, pick the place where you will study carefully as you want it to be as close as possible to where you want to work afterwards.
3. Are you experienced enough for an EMBA? That may cut you some slack in studying/score
Some other thoughts:
Looks like you took a course - did you get your money back from Master GMAT for scoring the same?
Any ideas why and what went wrong? why no improvement after 2 months?
What is your weakest area in Verbal?
P.S. Don't bother spending $50 to send score reports. Don't think it will be a big winner. I would instead retake one more time (I know it sounds dreadful) but your GMAT prep was 670 and you did take a course. I can't believe you won't improve. You should do at least 40-50 points better by just retaking (and your score reports are sent for free).
Assuming you have time to retake and spend 30 days - i would get either GMAT Club grammar book
(free download) or MGMAT Verbal Foundations
+ MGMAT Roadmap
and spend 30 days with them. If you can't improve 50 points call me a liar (I may call you a lazy bum in return though).
Also, take a quick look here: gmat fiction
- I highly recommend this for non-native speakers.
Founder of GMAT Club
Just starting out with GMAT? Start here... | Want to know your GMAT Score? Try GMAT Score Estimator
Need GMAT Book Recommendations? Best GMAT Books
Co-author of the GMAT Club tests
Have a blog? Feature it on GMAT Club!
GMAT Club Premium Membership - big benefits and savings