Hi Kamel,
A January 20th Test Date gives you about 4 weeks of study time, but it's not clear whether that will be enough time for you to hit 650+. Your studies so far seem like they might have been inconsistent - and many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so it's possible that you'll end up needing more time than you've planned for.
Since you have not taken any practice CATs yet, it would be a good idea to take a FULL-LENGTH practice CAT Test sometime soon; you can download 2 for free from
www.mba.com (and they come with some additional practice materials). That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
GMAT assassins aren't born, they're made,
Rich