Yes the y50 will cost more I don't by how much. Although you can still wait and see if it comes within your budget. http://news.lenovo.com/images/20034/Y,%20Z,%20C-Series%20and%20LBG%20Monitors%20Spec%20Sheets.pdf
About desktop, then you could consider this
CPU: i7-4770k Rs 23889.
Mobo: Asus Z87-A Rs 13568. although you can find better alternatives for this
RAM: 8 GB (2x4GB) Corsair Vengeance DDR3 4 GB (CMZ4GX3M1A1600C9) Rs. 2910*2= 5820
GPU: Sapphire Radeon HD 7850 2GB GDDR5 Graphics Card Rs. 14500.
PSU: Corsair VS 650 Rs 4100
HDD:WD Blue 1TB Rs 4100
Case: Antec X1 Rs 2400.
Total Rs 68377. (Prices are approximate, from www.flipkart.com)
Screen - benq Rs 3-4 k and a mouse/keyboard combo about at 2k and ups at 1-2 k. Anything else you can add and reduce on your own.