Hi aladiny,
Although I am unsure of how long you prepped for your first GMAT, since you seem to be stuck at a 580, you may considering adjusting your study routine, so that you can gain a more thorough understanding of both GMAT quant and verbal topics.
The GMAT is such a challenging exam because there are relatively few questions asked in a given exam, yet those questions come from a huge topic pool. Thus, the best way to get a great GMAT score is to have a thorough understanding of all the topics that may be tested on the exam. To develop such mastery, you want to strive for linear and targeted learning, and follow that with focused practice. In other words, you want to master one topic before you move to the next.
When studying verbal, focus on learning one section at a time: reading comprehension, sentence correction, or critical reasoning. You want to be able to learn about all aspects of critical reasoning (strengthen and weaken the conclusion, resolve the paradox, find the conclusion, must be true, etc.), for example. Follow up your learning with focused critical-reasoning practice, so you can determine your specific weaknesses within that topic. You should do the same for sentence correction and reading comprehension.
For quant, since you are stronger in that topic, you might consider following a similar but slightly altered approach that consists of more focused practice. For example, if you are reviewing number properties, be sure that you can practice 50 or more questions just from number properties (LCM, GCF, units digit patterns, divisibility, remainders, etc.). The results of that practice will help you determine your weak areas within that topic. Once you find and fix your weak areas, move on to the next quant topic.
You may also consider using other study materials, besides
the Official Guide, as your study resource. While
the Official Guide is a great book because it has official questions from past GMATs, it has limited instruction and does not provide full exposure to all GMAT topics. For your retake, consider seeking out some robust prep materials that provide sufficient targeted practice for you to discover and fix your weak areas.
Once you have improved your GMAT quant and verbal knowledge, resume taking practice exams. However, rather than repeating previous practice exams, consider taking some of the MBA.com exams, from either exam pack 1 or exam pack 2.
Finally, I have a couple of questions that will give me a better sense of your options. Do you have to take your GMAT in three weeks or can you push it to a later date? What deadlines are you targeting?
If you have any further questions, feel free to reach out to me directly.