That is one of the biggest downfalls of a laptop, I hate to say. This is the reason why I am reluctant to get myself one and opted for a laptop instead.
Unfortunately, its unlikely that you will be able to upgrade the CPU or GPU, the only way you would be able to do that is to get someone who knows about electronics, but I also doubt you would get any form of warranty.
Its best to buy a new one. I have heard that laptop manufacturers are starting to put expansion slots into laptops which would help in the long run. Try get something like that if there is such a thing out already.
