I don't know what your school's HESI test consists of, but mine had Vocab, Grammar, A&P, Reading Comp, and Math. I purchased the HESI Admission Assessment Exam Review book (3rd Edition) for about $40 and found it to be incredibly helpful for all sections except A&P. The A&P section in the book was just not thorough enough for me, but I found my old class notes helped a lot. I passed the test with a 93% overall.
I think the "A2" means "Admission Assessment," which is probably used to differentiate between the HESI entrance and HESI exit exams. I could be wrong, though.