Since the unit is out of warranty, Future Shop can send it to a service depot for you, where you can be provided an estimate for the repair. For out-of-warranty cases like this, though, I recommend dealing with the manufacturer directly -- they can often give the best price and fastest turnaround time on these kind of repairs.
Having said all that, though, it's very likely any repair depot will need to replace the entire motherboard for you. Not only will this be costly, but it's likely you'll end up with another of the same motherboard, with another defective nVidia chip. (The alternative is that they repair the motherboard you're using, which might be cheaper, but it's a bandaid solution at best.) Given your situation, consider a brand new laptop, as well.
