from what I have heard about Rosetta Stone, the level of language taught is quite basic. You won't get beyond beginners level to be honest. Also the method of learning may not suit you. There is no writing as fas as I am aware. The method of teaching used is basically picture recognition, so you see a picture of an apple and you say "apple" and you learn like that. If you have any aptitude for languages then there are other courses that would provide a much better learning experience ( including recognising how the language is written and spelt which is important if you are going to travel to a country ) and a more rounded grasp of the language. Also Rosetta Stone is quite expensive for what you get.
Perhaps try your local library for Pimsleur or other courses. Teach Yourself are very good courses also.
Best of luck with your language learning!