Rosetta Stone Greek Level 1 & 2 Win/Mac Personal Edition review:4 stars (An excellent second course) - The Rosetta Stone Greek Level 1 & II is an excellent second course if you want to increase your vocabulary and develop the kind of feel for the language that a native speaker develops as a child. The course is entirely in Greek, with no instruction in English and no explanation of Greek grammar.
If you want to learn conversational Greek for travel, then I recommend that you start with the Pimsleur Greek I course. Unfortunately, there is no Pimsleur Greek II course, so I recommend the Rosetta Stone course for your second course. You may also want to buy a dictionary for the occasional word that you will not be able to understand just from the pictures in the Rosetta Stone course. You may also want to purchase a book on Greek verbs to supplement the Rosetta Stone course.
One advantage of the Rosetta Stone course is that it will help you to increase your fluency at reading the Greek alphabet.