Looking to build a partial mid end gaming computer(processor, mobo and RAM only)

Hey everyone!

I want to build a mid-end gaming PC for myself for around INR 10000.(Building this with pocket money).
This is what I've thought of:
Pentium G2020(link) INR 3500

1x4GB Vengeance(link) INR 2900

Gigabyte GA-B75M-D3H(link) INR 4300

Total INR 10700

Any suggestions/changes/optimizations?

I have the following components:
Gainward GTX650 1GB stock(1.5 months old)
Month-old 24X DVD writer from LG
Corsair CX430 32A model (4 months old)
Reusing my Acer case which is mid-tower with USB2.0 and MicroATX board support at max
160GB SATA2 HDD(almost full)
60GB SSD(will install OS on this)
1TB external HDD(700GB free)
VGA 1440x900 Acer monitor (AL1916W)

Only want this build to last 2 years or so.
If I can reduce the cost of the motherboard, please let me know.

(NOTE: I had seen some H61 motherboards for around INR 3000, but those didn't support 1600MHz RAM, so if I want to go for them I'll have to drop the Vengeance and go for this RAM: link x2) INR 3800

However, it's a little costlier than the Vengeance, and wondering if the mobo downgrade is worth it.

Regards,
cst1992