Include monitor?
Alright, if you can, clean up the cooler, if you never clean it before, watch tutorial video on Youtube.

For 1K budget, you can fit these,

1. Another 4GB RAM - RM 125
2. Zotac GTX950 Single Fan - RM 699
3. FSP Hexa+ 550W PSU - RM 189

I googled the model of your PSU, seems like it is a 300W PSU, so PSU is recommended to change as well to run new GPU.

If you can spare another RM 100, go for Gainward GTX960 Reference (RM 799). CPU bottleneck might be possible but that's the solution for now, upgrade CPU next time when you have more money.

i3 is not possible with your budget, the cheapest i3 costs nearly RM 500 now.

Intel Pentium G3250 - RM 229
ASRock H81M-VG4 - RM 209
Kingston 4GB DDR3 1600MHz Value RAM - RM 99
WD Blue 1TB HDD - RM 219
FSP Hexa+ 400W - RM 129
Cheap casing (your choice) ~ RM 100

Total: RM 985

If you really want i3, you can just get those cheap case which bundles with PSU (roughly RM 100 in total for case + PSU), but you are warned that the quality of the PSU is totally unknown, don't come back and find me if anything happen to your PC