Hi Luis.
Given your section scores, probably, what you should do is topic by topic work on both quant and verbal.
That said, driving your quant score significantly higher would probably be easier that driving your verbal score significantly higher. For quant, you can drive your expected section score a point or two higher each time you strengthen a few weaker areas. So, if you strengthen, say, 12 weaker areas, you should see decent increase in your quant section score that would likely result in your scoring 600+ as long as your verbal score holds up or goes a point or two higher.
If it turns out that strengthening 12 or so quant areas and improving a bit in verbal is not enough to get you to 600+, your move is to strengthen some more quant areas.
Also, here's another thing to consider.
You should use official practice tests more.
What you have been doing is using Manhattan materials and Manhattan practice tests, and as a result, you have prepared for Manhattan CATs, rather than for the actual GMAT, which is somewhat different from the Manhattan CATs. That difference probably partly explains why your scores on official tests have been lower than most of your practice test scores.
Regarding being concerned that you will once again not hit your score goal, the fact of the matter is that, if you prepare effectively, you'll hit your score goal. So, make sure that you do careful, thorough, topic by topic work that truly results in your developing stronger skills.
For some more ideas, you could read the following posts.
Developing the Proper Mindset For GMAT SuccessHow To Increase Your GMAT Quant ScoreGet Excited About Taking the GMAT – You Might Just Earn A Higher Score