Hi Ver23.
The best way to increase your quant score is to master one quant topic at a time, basically driving your quant score up point by point.
To master a quant topic, you first learn or review the concepts and strategies associated with the topic and then answer dozens of practice questions involving the topic until you get them correct consistently. When practicing a topic, you should start off untimed and focus on learning and achieving high accuracy and then seek to work the time per question down until you can answer the questions in two minutes each.
By mastering one topic at a time, you'll eventually master the entire quant section and achieve your upper 40s quant score goal.
For some more tips on how to increase your quant score, you could read the following post.
How to Increase Your GMAT Quant Score: Top 25 TipsAlso, since consistency is key to achieving a high quant score, you could probably get some key insights from this post as well.
Improving Your Accuracy on the GMAT