Price and hardware choice will be different by next year so this is just a reference.
Intel Core i3 6100 - RM 499
ASRock B150M-HDV D4 - RM 399
GSKill NT 8GB DDR4 2133MHz Value RAM - RM 249
Palit GTX960 2GB GDDR5 Reference OC - RM 939
WD Blue 1TB HDD - RM 225
FSP Hexa+ 550W - RM 189
Bitfenix NOVA - RM 149
BenQ XL2411Z 144Hz - RM 1199 / Acer XB240H 144Hz - RM 1199
Total: RM 3848 (Idealtech price inclusive of GST)
As you can see, the monitor alone is already costing you RM 1199, so you will have to sacrifice other parts to cover up the cost, and this rig is over your budget by nearly RM 400. You can downgrade the GPU to GTX750Ti but I don't think it can push 144Hz in CS:GO/Dota 2 all the time at max settings, unless you are ok with medium settings.
Edit: Correction on CPU model.
Would it be possible if I were to replace the WD HDD with a 128GB SSD of about the same price? I already have a 2TB external HDD to store files. Can suggest a 128GB SSD of about the same price?