Stock up on any paper, pens or notebooks you may need prior to arrival. There is only one major bookstore that sells an array of stationary, however exercise books can be found in most supermarkets. Extra batteries for all of your equipment. They are expensive and difficult to buy. Alcohol, especially wine.
Indonesian beer is sold in most hotels and restaurants.
Fosters beer is available, and VB is occasionally available. However, prices vary between shops and hotels. There is virtually no good wine on the island, and what is available is expensive. Most journalists who have been in East Timor for some time are craving white wine. Chocolate, long-life dairy products.