Sneha, Welcome to the club.your prep material is enough, though I would add Math work book by Kaplan if your Math skills are rusty.

One comment you mentioned a book GMAT with professor Dave . Actually while I went to India and was researching about books, the shopkeeper highly recommended this book and said these days this is supposed to be a very good book. Based on his suggestion I bought the book but till now I have actually not read it.I have not heard any one mentioning that book in this forum though. May be others should provide their openion as well.At the end of the day it is also important to cover few important books and cover them well, rather then reading lot of material. It also boils down to how much time you have. Most of us preparing for GMAT also work so it is important to utilize the time we get.

My study plan is almost same as yours. Concentrate on the basics first before going ahead with solving questions. irrespective of the actual no of question you practice , your basics needs to be clear. The questions are often twisted and twicked so basics are very important.

While you are at the begining of your preparation timing is not very important. Once you learn th concepts and move ahead start concentrating on the timing.

Good Luck!