Please ensure your current GPU can be installed in the following casing (CM Elite 110), if it doesn't fit, you will need to swap to a slightly bigger casing like CM Elite 130. Same goes to PSU, if the power requirement of your GPU is higher than what the below PSU can support then you will need to upgrade the PSU as well.

Intel Core i5 7400 - RM 840
ASRock H270M-ITX/ac - RM 569
G.SKill Aegis 8GB DDR4 2400MHz RAM - RM 275
GPU re-use
SSD re-use
WD Blue 1TB HDD - RM 219
FSP Hexa+ 550W - RM 195
CM Elite 110 - RM 158

Total: RM 2256 (ETECH price inclusive of GST)

I would recommend i5 for smooth Sony Vegas operation.

Intel Core i5 7400 - RM 841
Asus H110M-K - RM 259 (BIOS update is required to run Kaby Lake CPU)
G.SKill Aegis 8GB DDR4 2133MHz RAM - RM 255
Gigabyte GTX1050 2GB GDDR5 - RM 570
Seagate Barracuda 1TB HDD - RM 219
FSP Hexa+ 450W - RM 169
Tecware Edge - RM 149
ViewSonic VA2419-SH IPS - RM 525

Total: RM 2987 (ETECH price inclusive of GST)
Build refined.

Intel Core i5 7400 - RM 840
ASRock H270M-ITX/ac - RM 569
G.SKill Aegis 8GB DDR4 2400MHz RAM - RM 275
GPU re-use
SSD re-use
HDD re-use
Superflower Leadex Gold 550W - RM 429
Fractal Design Node 304 - RM 369

Total: RM 2482 (ETECH price inclusive of GST)

Please make sure your current GPU can be fitted in the casing chosen above (if you aren't sure, you can state out the model here so I can determine for you).