Macroeconomics, by Mankiw
I am taking a course using the same Romer's book, and the book was used in our bachelor program. You can take an overall view by reading Mankiw's book, and then read the same topic by Romer.
Honestly, the stuf in Romer is difficult to followed, but easier if you ever try to read Lectures in Macroeconomics by Fisher, which is used as an advanced course for phd students specializing in macro
Good luck