Warranty extension question

[postdiction]

So I bought my thinkpad t400 a couple of months ago.

It comes with 3 year on-site next business day warranty.

This warranty expires in 2012 but, I was wondering if I find the laptop still fairly functional, would i be able to extend the NBD onsite warranty?

If so, what is the max # of years and how much? Also, is there a specific time when I have to buy the warranty extension by or do I have until the original warranty expires?

I would like to get the same NBD on-site warranty as this will be my only computer and I would not want to be down for very long.

Thanks,

postdiction