Here are some excellent Indian films you might want to consider investigating, of which the first eight are essential, all having been directed by the great Satyajit Ray; 
1 Aparajito
2 The Big City
3 Distant Thunder
4 An Enemy of the People
5 The Home and the World
6 Pather Panchali
7 Two Daughters
8 World of Apu
9 Bombay Talkie
10 The River
11 Salaam Bombay!
12 Shakespeare Wallah

I'm not sure if all of these can be purchased but make sure to check amazon.com and the other e-movie sellers, plus internet movie database is a great place to begin your search for any film (imdb.com), good-luck