Here it is on amazon
Get all the questions right! (haha just kidding). I would go over the grammar rules again. I would use College Panda's Writing book and Khan Academy. Here's something you could look at. I recommend this and the question of the day.
The College Panda's SAT Writing: Advanced Guide and Workbook https://www.amazon.com/dp/098949649X/ref=cm_sw_r_cp_api_i_WR12ZJH1GCXAWVSH6GQA
This book
For Reading, the best way to build a foundation is to do actual reading, and not of prep book content for that matter. And why wouldn't this be this case? Reading is the only section where every answer is provided to you; the obstacle is understanding the text of the questions, answers, and passages such that the meaning of each is in perfect alignment.
If you don't think Meltzer's grammar book is that helpful, try out an alternative in the form of College Panda or StudyLark; they are very solid substitutes whose quality I daresay transcends that of Meltzer's book.