Banks/Currency Exchange-- There are two new ATM locations in Senggigi: Bank BDI (next to Silkair and the Pacific Supermarket) and Bank BCA (near the turnoff to the Senggigi Beach Hotel). Money-changers also abound.
Health/Safety-- Lombok's monkeys are high-risk for rabies, so don't feed them, wear long pants and closed shoes, and don't provoke them. If bitten, you'll need to begin the series of rabies shots immediately (don't listen to anyone who says otherwise).
Internet/E-mail-- Senggigi Beach has several cafes clustered along the southern end of Jalan Raya Senggigi (near Bayan Restaurant).
Post Office/Mail-- There are post offices in Mataram and one in the center of Senggigi, but your hotel can also mail for you.