What is the right time to apply for the foreign universities (esp. US) for MS course?

i need to take up my GRE exams.. i wud like to know when the universities start takin in applications for the course starting from 2008.. (i wil be finishin my undergrad by june 2008).. also what are the other requirements??

Can the mathematics GRE make up for a lack of math courses in my records for an economics PhD application?

I did my undergrad at a school where there wasn’t any choice to take advanced math courses (outside the US) and my master’s in the UK doesn’t have a strong math component. Can the GRE in math make up for that in my application?

I am using my refund check from school to purchase a much needed laptop, what is the best brand I can buy?

I am a college junior and I have never had the money to buy my own laptop for school. Finally, due to hard earned scholarships this semester I am receiving 00 in a refund check and I want (really need) to buy a laptop for the rest of undergrad and graduate school. I would like to know what is the best (most reliable, fast, less likely to crash, and will survive graduate school) laptop to buy

When is the best time to start study for GRE?

Before or after Undergrad.?
How much time ahead of time if so?
How many times do they sit exams?