I looked up some support for your laptop on HP.com, and found a couple of things. Here is the link to the website that has some ideas:
I would start with Method 4. This has you disconnect any and all computer that are connected to your network. Then try playing the game in your case, and see if there is still lag.
If there is then they recommend that you test you modem and router, I don't think that they are the problem, but there is always a chance. All they have you do is do a power cycle, I don't know if you have tried that or not. You also might want to try to upgrade your routers firmware, just to stay up to date.
Hope this helps. If not post back and I will see what I can to for you.