I've found one can learn a lot just from the local public library. At least here, in the US for most people. I don't know what resources are like for you in Sri Lanka but if you have a Tamil???-English dictionary and the internet you can learn from newspapers and so on. It takes a lot of time but (for me) but I am progressing. (German, in my case) It says Sinhala, but also "other". I'm not at all familiar with Sinhala.

I can help you for free!

Good Luck :D

I am teaching willing to teach you but I charge 50 itc per hour. Please let me know if you are interested.