The existing graphics is not a card or even a chip. It's built right into the i3 CPU.
http://www.notebookcheck.net/Intel-HD-Graphics-2500.69812.0.html confirms that even on low settings gaming is barely passable.
Now PC gaming is all over the map but I don't see a budget here. Maybe it's best to get some PS4 or XBOX One here? And if you have friends that can help you build a gaming PC, consider this list -> https://www.reddit.com/r/PCMasterRace/wiki/builds