Firstly, you don't have to make a new post each time you want to post something. You can just use the edit button at the bottom right corner of your post.
You'll need a graphics card powerful enough to support 2 monitors. What you buy depends on your budget.
The 17" LCD will cost you approx Rs. 12,000. The graphics card can range from Rs. 2,500 to Rs. 25,000. It's all down to what you can afford.
Once you have the necessary hardware, connect both monitors to the graphics card.
Right-click on the desktop and choose 'Properties'. Choose the 'Settings' tab and enable your second monitor from here.
It's really easy and self explanatory.