if i am not mistaken then according to that model number, your laptop has a i5-4200u cpu with intel hd 4400 graphics....these specs should run dayz fine on low settings, in very detailed areas some lag maybe noticeable but otherwise you should be fine. I can say this with confidence because my laptop has a i5-3337u with intel hd 4000 ...yours fairs a bit better in the performance comparison so you should be fine. As someone has already mentioned, Dayz will be getting a newer engine, i'm not sure what that means in terms of minimum requirements to run the game, but i'm guessing the newer engine will be much more efficient and so will require less performance to run the game
EDIT: yes you can not upgrade a integrated chipset in a laptop, unless its a gaming oriented machine with a spare pci-e 16x or 8x slot...but for your case, no you cannot upgrade your graphics chipset