Hi giuliab3,
There are a variety of different ways that you can study for the GMAT, so it might be that the materials that you have now will be enough to help you get to your score goal. That having been said, based on what you described in your last post, there are two areas that you should look to change immediately:
1) Consistency in your studies. It's not clear how long you studied "just weekends only", but considering you've been studying for just 4 weeks, the amount of time that you've consistently studied (throughout the week) is relatively small. It's also not clear what your actual score goal is, but assuming it's around 700 or so, then you'll have to put in a significant amount of consistent study and effort to hit that goal. The sooner you can build a proper study routine (that you can stick to), the better.
2) Taking your CATs in a realistic fashion. Taking a CAT to 'see how you handle' just one section is a WASTE of a CAT. We need to assess your overall skills at regular intervals throughout the study process, so you have to be disciplined enough to take each CAT in a realistic fashion. There are aspects to the GMAT that you can really only learn to deal with by taking FULL CATs in a realistic way - and so far, it does not sound like you've done that (and as such, there is a question as to how accurate these CAT results really are). For now, you should focus on your studies for at least another 2 weeks, then take a new FULL-LENGTH CAT. Once you have that score, you should report back and we can discuss the results.
GMAT assassins aren't born, they're made,
Rich