Hi ForzaInter,
Many Test Takers are unhappy with their initial practice scores, but you really shouldn't be. That 450 is just a measure of your skills right now - and you'll improve on that result over time as you learn more about the content, Tactics and little 'secrets' of the Exam.
While it's understandable that you might want a Q51 (since that's the highest possible Score in the Quant section), it's not clear whether you actually "need" to earn that type of Score or not. By extension, you might end up spending far too much time trying to hone all of the skills needed to score that high and not put enough effort into your Verbal studies. From your posts, it's not clear which Schools you are interested in (or might be interested in in the future), but if you're planning to apply to any highly-competitive Programs, then you will almost certainly need a strong OVERALL Score - meaning that you'll need to perform at a high level in BOTH the Quant and Verbal sections. Thankfully, you appear to have given yourself lots of potential study time - which is great!
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on your timeframe and your goals:
1) What study materials do you currently have access to?
2) What is your overall goal score?
3) Have you given any though yet to which Schools you might want to apply to?
GMAT assassins aren't born, they're made,
Rich