You have not stated your TARGET GMAT score, so it will be a little difficult to suggest whether you should be ready to take the GMAT by end January. Secondly,you forgot to mention whether you're targetting the fall 2011 session or the Fall 2012. Assuming you're targetting fall 2011 session,I think you should be done with the GMAT latest by mid Feb(if you're not targetting tier 1 schools). I think before setting out on your preparation, you should have researched well on the quality of material you were referring. If you read reviews about the Princeton Review material, the general consensus here on the forum is that it sub standard if you really want to nail the GMAT. I remember I had initially referred PR and Manhattan Review material and found them to be too easy for my liking.
If you want to score well, you need to be strong in your fundamentals. I suggest that you order MGMAT Quant books as they're supposed to be the best for Quant. For Verbal, you may refer Aristotle SC Grail/MGMAT SC Guide and for RC, RC99 is a must have. I have heard that the Aristotle Prep has released the 2nd edition of SC Grail which comes with practice questions,so I think that you'd better prepare you for SC.

Talking about the tests, PR tests are way off the mark and generally not considered good. Take MGMAT tests. The tests are tougher than the actual GMAT especially the Quant section but they'll really prepare for the actual thing.

Focus on strategy: Maintain an error log. As you'll keep on hearing here from all the members, "quality' not quantity is the key.
And keep participating here. You'll find that this community will help you at each stage.

I think the best thing you can do is stay motivated and study hard. I would suggest that you analyze your performance heavily and focus on the areas that really hurt you. A lot of people bomb the GMAT their first time and bounce back and beat it their second time. Good Luck!

JL