Theres not a lot you can do with that laptop. Software can't fix your hardware restrictions. My laptop has an i7 6700 HQ, 16GB of RAM and GTX 960M 2GB VRAM and still cant run LSPDFR at stable FPS at all times...
Im afraid you'll have to do the same as me and build a cased PC because your hardware is not letting you expand your options on GTA 5...
You'll need at least 16 GB ram for GTA 5, being shared by 2 RAM cards, 8 GB each in order to divide the load and have room for graphical variations and a 4GB VRAM GPU too If, you're still intesrested in finding a local solution, remove the TXAA and VSYNC maybe? Like I said, you're pretty much limited with that hardware.