Its true that there is the heat issue regarding the Lenovo Y480 but that doesn't stop people from buying it anyway 
You can get a cooling fan if it helps 

Asus N56VZ is 15".

Another 15" laptop you can consider:

Dell Inspiron 15R (Special Edition), i7-3612QM + AMD HD7730M@RM2799, 8GB, 1TB(5400rpm); backlit keyboard optional

The rest with better GPU exceeds your budget 

14"-17"? Since light weight is required, 14" maybe? 
You're usage does not require strong raw processing power so i3/i5 will suffice 

Can try these:

Toshiba Satellite L840-1026X/XR/XW, i5-3210M + AMD HD7670M@RM2399[2.12kg], 4GB, 640GB, W7HP; colors: Black/Red/White, 3 years warranty
HP Pavilion G4-2006/2007/2008TX, i5-3210M + AMD HD7670M@RM2199[2.19kg], 4GB, 750GB(5400rpm), W7HP
Dell Vostro 3460, i5-3210M + Intel HD4000@RM2499[2.23kg], 4GB, 500GB(7200rpm), W7HB; colors: red/silver/bronze
Lenovo ThinkPad Edge E430, i5-3210M + Intel HD4000@RM2799[2.2kg], W7P, 4GB, 750GB (5400rpm), anti-glare

I'm not sure on the price for SSD. But I think you can get a 256GB SSD with these laptop.
Are you replacing it with the optic drive? 

Can consider all these:
14"
Acer V3-471G-53214G75, i5-3210M + Nvidia GT630M@RM2099[2.3kg], 2GB, 750GB W7HP, 3 years warranty
Asus A45Vm-VX113v, i5-3210M + Nvidia GT630M (2GB)@RM2099[2.4kg], 2GB, 500GB(5400rpm), W7HP, 2 years warranty
Dell Inspiron 14R, i5-3210M + Nvidia GT630M@RM1999[2.38kg], 4GB, 500GB(5400rpm)
HP Pavilion G4-2132/2133TX, i5-3210M + AMD HD7670M@RM1899[2.19kg], 2GB ,500GB(7200rpm), W7HB, colors: white/black
Lenovo Z480, i5-3210M + Nvidia GT630M@RM1999, 2GB, 500GB(5400rpm), W7HP, colors: grey/red/blue
Toshiba Satellite L840-1024X, i3-2370M + AMD HD7670M@RM1849[2.12kg], 2GB, 640GB, W7HP

Its hard to tell which one is more reliable since all of the are electronic devices, there will always be the probability of choosing a faulty one
In which's case its better to have a laptop with better warranty support/ coverage. If your budget is tight, then the Acer and the Asus would be good picks since they come with 3 years local and 2 years international warranty respectively

Otherwise, just go and try out each laptop, and then buy the one you like the most, then fork out a little bit more for warranty extension 

I apologize for my ignorance on desktop hardware performances haha...
The best GPU that you can get for a budget of RM4k is a GTX660M

15.6"
Asus G55VW-S1095V, i7-3610QM + Nvidia GTX660M (2GB) + (1920x1080)@3999, 4GB, 1TB(5400rpm), W7HP
Lenovo
Y580, i7-3630QM + Nvidia GTX660M + 1920x1080 @RM2999[JBL], 4GB, 500GB(5400rpm), W7HBasic, backlit keyboard, 2 yrs warranty, P950 headset
Ideapad Y580, i7-3610QM + Nvidia GTX660M (2GB) + (1920x1080) + Bluray@RM3599[JBL], 8GB, 1TB HDD(5400rpm), W7HP, backlit keyboard, 2 years international warranty
MSI GE60, i7-3610QM + Nvidia GTX660M + (1920x1080; anti-glare) + Bluray@RM4199, 8GB, 1TB(7200rpm), W7HP, 2 years warranty, gaming mouse & backpack, Free SteelSeries QCK Mass mousepad
I'm not sure whether its better than the desktop version of the GTX550M or not