Not being good at verbal is a common issue for most non-native speakers. But if you approach it in a structured manner, you can get substantially better over time.
You'd have to dig deeper to identify if the problem is with at the conceptual level or with speed.
For the former, check out the resources on GC, including the sub-forums here -->
GMAT verbal.
For speed, the more you practice simulating real conditions, the better you'll get. If you've exhausted the diagnostic tests from the material you've listed, here's more -->
GC Test Center.
Keep in mind that you are also racing against time for the main applications as well. If you can get a good score in the next month or two, you can target Round 2 deadlines for many bschools.