Textbook or Study Guide for Preparing for APWH

As an international student self studying for AP World History, should I buy an additional textbook or just rely on Barron’s study guide? I have three months to prepare for this exam, and even though I’m taking a World History course at my school its curriculum is different and it isn’t even taught in English. So a study guide/textbook will be all I have. Please answer according to that.</p>