For your budget , i suggest you go with following upgrades..
1. Sempron 3000+ (1.8GHz,128KB L2 cache,1600MHz HT bus,754) Rs1900
2. ASUS A8N VM Rs3700 (onboard usb ports, lan.. sound.. gfx etc etc)
3. 80 GB SATA Rs2050
4. TRANSCEND DDR 256 MB Rs1450
5. SONY DVD writer - 1900
TOTAL =...