Could this also be "the last two hours" (as in the two hours that have just passed)?
My wife says yes, given an appropriate context. E.g. How long did you watch TV? Dua jam lalu = For the last two hours. When did you watch TV? Dua jam lalu = two hours ago.
Sorry, but for "how long did you wacth tv?" You can not use "dua jam lalu". That is a question for a duration, and the answer should be something like "selama dua jam" (as long as two hours) or "selama satu bulan" (as long as a month).
"Two hours earlier" is equivalent English
so is "ago"
"Two hours before" should also be accepted