GMAT Strategy

I have made two attempts at GMAT and got disappointing scores. I seem to be unable to convert my preparation into a good score on the test day. Would appreciate any inputs on a number of queries I have. My journey so far and the queries are below:

I first wrote my GMAT in October 2010 with reasonable preparation - largely focused on OG 11 and OG 12, MGMAT SC and few full tests from Kaplan and GMATPrep. The lowest score I got was 640 and closer to test date; I was hitting close to 680 in Kaplan tests and thought that I was ready to score in the vicinity of 700 at the real thing. I wrote the test only to end up with a disappointing 640 (Q48, V29). I thought that my preparation was severely lacking and I need to do a lot more to really reach my target score.

In February this year, I started thinking about the second attempt and finished following material over 3 months or so:

Quant - OG 11 and 12, GMATClub forum questions (and there are lots of them and really good quality too)

Verbal:
Apart from OG 11 and 12, I also finished following material for specific sections
SC - MGMAT SC, Aristotle SC grail
CR - Powerscore bible
RC - RC99

I also took lot of full CATs once my material was over. Following are my scores for those CATS

MGMAT 1: 710 2: 700 3: 750 4: 730 5:770
Kaplan 1:690 2:700 3:690

GMATPrep 1:710 2: 740 1 (Reinstall): 660 - I did this immediately after I finished MGMAT 5 (complete four hours) and realized that it is futile to write a test when one is extremely tired and drained out 2 (Reinstall): 760

My lowest Quant score was 49 and verbal score range was 36-45. Only once (in the GMATPrep 660 one), I got 32 in verbal. Finishing all the material and armed with consistent CAT scores across tests (GMATclub score predictor was predicting a 730 score), I was feeling confident of getting around 730 at the real thing.

On the day of the exam, this is how it all went:
QA
The section started as a breeze - at least till 15th question, I felt completely in command of the section and thought I was managing pretty well and kept solving every question that came my way. Next thing I remember is having about 15 minutes left for last ten questions - I felt myself rushing through last ten questions and got a feeling that I had to make 2-3 wild guesses. Overall, I thought I lost my way a little in the end.

VA
The section was going OK - was not sure of my accuracy for some CR questions. RC is generally my weak area and hence I was not sure if I was doing well there or not. But, I had felt such uncertainty every time in practice CATs and broadly did OK there, so I kept going. Here again, I realized that I had 9 more questions to go with only 15 minutes left and then I got a long RC passage, completely messing up my time management. Like Quant, again I felt I rushed through in the last 8-9 questions and felt a little let down with that aspect of my performance.

In the end, I managed a poor score of 660 (Q47, V34). I had managed 5 points improvement in Verbal but lost a point in Quant and overall managed to pull up my score by just 20 points - nowhere close to my practice scores or the scores that I need to make my application competitive.

Questions I am grappling with now are:

1. Should I retake the test? If yes, what more can I do and how do I check if I have really made progress in my preparation?
2. Should I blame my overall low score on just the time amanagement issue in last 10 problems in both sections or does this score indiscate that I am being naïve in believing that my preparation levels are at 730+ right now.
3. I never felt timing stress in any of the practice CATs I took. The questions I saw in test were very similar to OG and GMATPrep kind of questions, so what could have led to timing issues on the real test.
4. If I sould retake, should I do this at the earliest opportunity 931 days) or should I wait for 2-3 months or so.

Comments/suggestions/help welcome.