Your amount of RAM should be on the "About this Mac" page, like
here, so you were probably looking in the right place anyway.
If you need more than what you currently have installed, you have to add or swap out memory modules.
Make sure to get the right modules though and check what the maximum amount of RAM is your machine can take (and the individual RAM slots).
What kind of machine do you have? I see in the other thread you have an Intel Core 2 Duo with 2 GHz and Snow Leopard installed already.
The VRAM you probably found under "More info..." -> "Graphics/Display". This is the Video RAM, meaning the "buffer" that is built into your graphics card. So unless you swap your graphics card for one with more VRAM you cannot increase it.
Onboard PC graphics cards often use part of your PCs RAM (shared memory) but I am not sure such a thing exists in the Mac world.