"Would you be kind enough as to let me know where can I buy Tunisian crochet hooks as the ordinary crochet hook would not be enough to hold the amount of stiches?"
Thanks for the great question!
The last time I visited Hobby Lobby, they had a good selection of Tunisian crochet hooks. If you have a Hobby Lobby close by, it's worth checking there.
I bought my favorite Tunisian hook at my local Joann craft store, but they don't have many sizes. The store close to me only had a J. That's the size I use most frequently.
If you shop on the Internet, there are many places you can buy them. This Pricegrabber link will take you to many different options:
Compare prices on Tunisian crochet hooks, also known as afghan crochet hooks.