You are putting the cart before the horse. Stop focusing on the "JLPT grammar points," focus on learning the language. You will never pass 2kyuu by studying the little bits and pieces, you have to gain a better overall mastery of the language.
Consider that the placement test you took might have been accurate. "Finishing" a textbook is not the same as mastering a textbook's material. My teacher used to say that the first 2 years of Japanese study (full time college level study, to be specific) contain all the material necessary to master the language, after that it's mostly just new vocabulary and some idioms. So if you didn't master the early material, you better get a handle on it NOW, before you even think of progressing.
If you're still working from intermediate textbooks, just put aside your thoughts of 2kyuu for now. At the pace of full-time college study, any student could pass 3kyuu at the end of second year, but only a few students could pass 2kyuu at the end of 4th year (and all of them would have spent substantial time in Japan). The gap between 3kyuu and 2kyuu is huge, it is the difference between being a student of the language, and a user of the language.