Translation income

Hi

I am a Translator and I earn through translation from English to Vernacular languages. All payments are received in electronic form.

While few clients deduct TDS @ 1%, there are clients who are not in based in India. However all payments are received in INR.

My questions are

1. Am I allowed to file my Income tax under sec 44AD

2. Do I need to pay Advance tax? If yes, As I am not sure the earning potential for the qhole year. So how should I compute Advance Tax?

Thanks for your time in advance.

Giridhar