This is the gpu you have NVidia 8400m GS, while it is a dedicated gpu it is also on a dell, also sold on hp and many others. most of the time big box brands dont allow you to upgrade much without upgrading a lot, they call it propriety. Meaning you won't be able to swap out your cpu either unless you replace your mobo becuase everything is soldered into place. and finding a non-propriety mobo to fit your laptop case with the right connections in all the right places will be tough. and truly if you open up your laptop you'll see what i'm talking about. sorry to be a bubble buster.
kurt