Your battery is generally covered under manufacturer's warranty, yes. Depending on the manufacturer of the laptop, Future Shop may be able to facilitate sending it out. Either way, you have the option of dealingwith the manufacturer directly.
There may also be nothing wrong with the battery -- in some laptop models that didn't come with Windows 7 originally, there's a bug that incorrectly reports how long the battery will last -- my very own LG laptop has this same bug. There's nothing wrong with my battery -- Windows 7 just doesn't see it properly. There could very well be nothing wrong with your battery, assuming it didn't have issues until you upgraded to Windows 7.
Whatever the case, it couldn't hurt to speak to your manufacturer anyway, to see if they have a solution yet, or if they'd prefer to test your battery.
Hope that helps!
