It depends on what are you planning to do. If you use the laptop for anything apart gaming or graphics intensive applications, I would keep it. If not, get any modern laptop with discrete graphics.
Comparing the 3rd and 7th gen Core, you will get about 20% more performance clock by clock and perhaps double battery life.
In my opinion, I would keep it unless you want something different, for example a smaller laptop or with graphics.
You could install a SSD and it will bring a new life to your laptop.
Regards