Need tips to score 650+ :-exam on Nov 16,should i postpone?

Hello all

I am amazed how people are able to score 700+ easily. I am struggling bb. Terribly struggling.
To brief... I started perparation on 16th July to be exact. First diagnostic I scored 570. I thought I have some hope. But after that I have given atleast 4 more exams and I am just coinsistently scoring in same range.

Princeton-570
gmatprep-590
kaplan-520
mgmat-520

I have realized that timing is one problem for me. I am struggling thru last 5 to 10 questions during the test. So I am keeping timer during practice sessions now. But even other wise, other 2 problems I have - silly mistakes, and - some questions like 700+ level questions, I am stuck. I meaning, I cannot even think through the problem calmly. I get irritated I dont know how to solve it.

I work full time and have a 18 month old at home. So it is extremely difficult to find time to study. Still I have been counting my hours of study - almost 100 hrs till now. But I dont know if it has been any helpful. I have booked my exam on 16th Nov. I am rethinking about it now. I dont know if I should may be postpone it. I am aiming for University of Florida part time MBA program here in sunrise florida. So I would like a score of 650 atleast to be comfortable to send the application. But I would like to apply for other colleges out of state as well. So a score above 700 is like a dream right now.

I would appreciate advice about scoring and also about apllying information to UFL - anyone who got into UFL part time, can you please give me some tips?

Sincerely,
aiming to scoremore.