Most people don't see much difference in score in one week - so, no, that isn't unexpected, and no, you should not just give up.
You should expect to spend more than 2 months however. Most people need 3 to 4 months (and sometimes longer) to increase 100+ points.
If you would like advice on your study plan, use the below article to analyze your most recent MGMAT CAT:
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and tell us your analysis (note: NOT just the raw data; we want to see your analysis / what you think the data means), and we'll discuss!