Im posting what materials I used. will further post my experience tomorrow
My main point is that if you want to increase your GMAT score in a short period of time, then practise with SC. SC is the only section which you can improve easily in a short period of time. It is very difficult to increase your RC skills in a short period of time. CR is also difficult to increase within few weeks. Furthermore, SC is the most heavily weighted part of the exam.
Useful practice materials:
OG 10 -->
really useful
Gprep -->
the best practise material. There are two versions, the one launched in 2006 and, in august 2008, GMAC launched a new version. I feel that the new version is tougher than the old one. The new version has a lot of questions from GWD (known as Sets in this forum).
There are in total more than 500 SC questions, 150 CR questions, 35 esseys and 118 questions, 400 PS questions, and 450 DS questions.
GWD really useful.
Useful internet sites:
-Testmagic
-Manhattan GMAT Forum
-Beat the GMAT
-Chasedream
Practice materials partially useful:
Feifei Logics: the questions are good but the explanations are bad
LSAT exams: good to practise some.
XDF SC Baiyong: good practice material, however, a lot of questions are from OG
XDF Logics: really good for practising, there are more than 600 pages of CR questions.
Practice materials I feel not useful at all
OG11: a lot of people have good words for OG11 but I personally feel OG11 useless, it is time-wasting to practice with this book because the questions are really easy and the explanations are bad.
Kaplan: did not practice much but I think it is not useful
I suggest everyone not to spend money on fancy and expensive GMAT preparation courses or materials. Now looking back, I think everyone can pass GMAT only by practising with Gprep, Sets and OG10.
Reading Comprehension
I am sorry, I cannot really suggest you anything in this section as I went to college in a English speaking country and did not have problem with reading comprehension. The only think I can suggest is to practice with Gprep. However, your should is better spend in improving your SC skills than in your RC skills.
Furthermore, instead of reading carefully everything, you should learn to find answers to each question. For example, this question is taken from Gprep:
The passage suggests that modern multinationals differ from early chartered trading companies in that
Look in the text the sentences around the words: chartered trading companies. If
In reality, however, early trading companies successfully purchased and outfitted ships, built and operated offices and warehouses, manufactured trade goods for use abroad, maintained trading posts and production facilities overseas, procured goods for import, and sold those goods both at home and in other countries. The large volume of transactions associated with these activities seems to have necessitated hierarchical management structures well before the advent of modern communications and transportation. For example, in…
Go back to the beginning and you see the word however, then stop there because it means that everything before the word however does not concur with the point after the word however. Also stop after for example because after that, the author is only giving samples and not useful to answer the question. | 
