The GTA series is not considered "light" unless you are excluding GTA 4 and 5. GTA 4 is a very bad port when it was released which could mean GTA 5 will be another bad port. Bad ports means higher system requirements.
If a 14" laptop is fine, then consider the $699 Lenovo Y410p it has a GT 755m graphics chip which is slightly more powerful than a Radeon HD 8850m. Both of those chips would simply crush the performance of the AMD Radeon HD 7660G + 7670M Dual Graphics in the above suggested laptop with ease.
http
/shop.lenovo.com/us/en/laptops/ideapad/y-series/y410p/