I really don't know how much the costs will run for. But when I got a quote for health insurance in 2009 june/july, it was around $150 per month. But if you buy it in USA they will do the evaluation and send you for medical checkup and evaluation which will make your premium to go up . But if you were to use the second link, they will not need any pre-evaluation or anything. If you have a visa or mastercard you can buy one from there. But if you come here a week before your program, you might be able to find a good a good and cheaper plan.
Don't just buy it yet.
good luck