Hey, tatitati! Congrats on your upcoming trip, and kudos to you for doing research before you travel! When you're adding a one week data pass to a pay as you go account, the data continues at lower speeds once all of the high speed data is exhausted. That said, accounts with an existing data pass that have used up the high speed data can absolutely add an additional data pass before the existing pass expiration date, so if you're wanting to add another 1GB data pass before the initial week is up, you're free to do so as long as you've exhausted the high speed data on the original pass first!
Okey, Thank you! Can you add more data online from your personal sites? Or do you need to do this by phone or store?