yeah that's a pretty old laptop, so it has to work hard.
as suggested you can get a laptop cooler.
another thing you can try, I'm guessing the battery is close to being dead, so it probably gets really hot, pull it out and run the laptop without the battery, it will get you an extra hole in the casing to vent heat and get rid of one of the heat generation entities.
another thing you could try is get MSI after burner (or you can do this through BIOS, I think msi is easier) and under clock the CPU and GPU. It will lower the responsiveness but will lower the temperatures too.
alright, hope that helps you get by till you can get a new one.