Your laptop came with nvidia-optimus technology. This should work in the following way: Most of the time, the system runs using the Intel graphics, which improves the battery life, and when you need to use more graphic power, it switches automatically to the nvidia card. The problem is that there is no official support of the optimus technology on linux. There are, however, some projects trying to solve the problem, see for example the hybrid graphics at launchpad https://launchpad.net/~hybrid-graphics-linux .
So don't worry, your laptop does have the nvidia card. It's just that it is either disabled in bios (and you can enable it), or your computer cannot see it. Anyway, if you want to use the card, you will have to install software enabling you to switch between the graphics cards.