Your router's IP is given to you by your ISP.
To reset it, it is usually as easy as unplugging your router and powering it down for 30 sec and then plugging everything back in.
But if that doesn't work, then you might need to contact your Internet Service Provider.
Also, you should run malwarebytes on every computer that could be connected to your internet.
Not only that, but it might also be a good thing to change your wifi password.