Hey guys warning - long post

So, after going trough the part on quantitative section on a McGraw-Hill GMAT book (which i didn't like), I went to my local foreign language bookshop and got the Official Guide, 12th edition, and Kaplan GMAT premier 2011 (they had the official verbal and quantitative guides as well, but they costed 35 euros each, that's ridiculous, i'm gonna buy them online if i have to!)

I decided to took the diagnostic test in 2 separate sittings for quant and verb.
I decided for a slightly more realistic approach than the one suggested, by timing myself* and not going back to change previous answers.

*i kept myself under 2 minutes per question, except for a problem solving question which i knew i could solve, but got stuck during the calculations. i got stubborn because it look really easy, and spent 10 minutes on it before swearing, scaring my dog and randomly guessing. i guessed wrong, and after i finished it was actually pretty easy :/

So, my scores are (brackets indicate the "result" indicated in the book)

Problem Solving: 18/24 (Above Average)
Data Sufficiency: 15/24 (Average) - Ouch!
Reading Comprehension: 16/17 (Excellent) - Whoo-hoo!
Critical Reasoning: 13/17 (Above Average)
Sentence Correction: 14/18 (Above Average)

So i guess it's not that bad a starting point - but i really thought i'd score higher on the quantitative section (i'm a student of economics, always been pretty good at maths) and lower on the verbal one (I'm obviously not a native speaker).

What I'm trying to do now is to analyze this test results to come up with a study plan to strenghten my weaknesses. For now I'm just interested in the quantitative part since apparently the verbal one is not as scary as i thought.


What i'd like to do is to assess my weaknessess more accurately. What should i do now? study the math review parts on the kaplan and OG12, and then take all the practice problems to see how i score and figure out if i need more material?