It would depend on the laptop you have, but graphics slots on laptops are extremely rare, and typically only used for higher-end GPUs. I highly doubt you can change the GPU inside of that laptop, though there are some ways to improve the performance in games if that is what you are after.
Yes, like I was saying, you can't remove that graphics card. In fact I also have an NP300E5C, and the GPU is soldered into the motherboard. Almost all laptops are like this. You will probably never own or see a laptop that has a removable GPU, they are extremely rare.