First, you have to believe in yourself. If your high school is not bad, 70-80 (full mark 100) should not be bad. If you study hard in senior three, it is absolutely possible to take the liberal arts math test 130. If it is 150, don't be discouraged. Then you have to work harder, work harder, and understand all the questions in class first. You can make some plans for remedial classes in the summer vacation of senior two, which is a supplementary foundation for people with weak foundation. If you don't have any ideas, look at the examples and methods, plus the comprehensive review of senior three, it is still possible to reach 130.
If your high school is average, you should work harder yourself. First, do the basic questions well, grasp the basic points, then read some guiding books, read more classic examples, practice more and ask more questions as appropriate, and then pass the training of senior three. It is still possible to take the exam before the college entrance examination 130, although it is difficult. I suggest you don't set too high a goal at once, but step by step, first to the passing line, then to 120, and then to higher. Remember not to be anxious, but to have confidence, sometimes the mentality is the most important.
As for the reference book you mentioned, it's hard to say because I didn't take the national examination. I can only talk about my personal experience for reference only. At that time, in addition to the information issued by the school, I also bought a reference book of Longmen, which also contained many examples of the national examination. Personally, I think this set of books explains examples in detail and is very helpful to solve problems. Finally, I wish you success!