Hi Lawret,
Happy to hear about your GRE plans.
The first thing that you must do before you join any class is to take a GRE prep test on the ETS website. This will give you a fair assessment of your performance, strength and weakness on the GRE.
To answer your question about GRE courses, at CrackVerbal we have an online course that teaches all the concepts and strategies for GRE Verbal and Quant. Most GRE aspirants find Verbal as their biggest challenge on the GRE - mainly because the test requires you to remember some really difficult words. We address this through a set of 500 verbal flashcards that are designed to help you memorize GRE words.
We also have a mobile app that allows to learn these high frequency GRE words - its called WordToonz. The app is available in both iOS and Play store for free download.
If you would like to watch a few concept videos on GRE Verbal and GRE Quant, please visit the CrackVerbal GRE Online course and you will be able to watch a preview of the videos as well.
Hope this helps