Chances are you are better off building a new laptop.
I am not aware of any laptop that does not have the graphics card built into the mother board itself.
Not true. There are many laptops where the G. card is not built into the mother board. It is especially the case for high-end laptops, or the ones targeted specifically for multimedia and gaming fans. But probably less than 5% of all laptops sold.
Its very unlikely, almost impossible being that you are considering an upgrade, that your laptop has a graphics card that isn't built into the motherboard. It doesn't matter if the memory is dedicated or shared if the card is fused into the mobo.