If its possible to take another class with a different professor next semester, I think a class would be more helpful. Either way, it will take time to take the language and Rosetta Stone is certainly a good start/companion to a class. 

In my opinion, RS may serve only as an additional tool, it certainly helps grasp some vocabulary and sentance structure, but you may want to get some grammar explained, and write down some words and phrases that may not occur again, perhaps make and use some flash-cards. If you add a little listening and reading practise, this pretty much will be a learning prosess. But I think that RS as all-in-one learning tool is a word of marketing.

I don't rate RS very highly. I think it made me lazy as quite often you're just clicking on pictures. It can help with picking up some vocab but I don't think it does much with grammar. It's not worth the money. I think it you're going to spend money on learning materials I'd recommend Michel Thomas's course as it really makes you work hard and you start to pick it up. It's also cheaper than RS as I recall. It also makes you feel like you're involved in a class due to the way it's designed.

I highly recommend the Teach Yourself series. I learned a lot from Teach Yourself French. Have a look at RF1 also, they have a "radio français facile" which is quite helpful. You can listen to the news and check the transcript so that you get used to spoken French easily. Here's the link:

http://www.rfi.fr/lffr/statiques/accueil_apprendre.asp

Watch movies. Listen to French music. Is there anything you are really passionate about? Why don't you try to read about it in French? Even the French Wikipedia would help. Since you're already familiar with the topic, it'll be easier for you to grasp the content. You can also get a few paid lessons here on italki. There are tons of teachers here and I'm sure you can find one adequate to your learning style and needs (and no, I'm not being paid to advertise lol).

The important thing is: try to get as much contact as you can with the language, especially real language, used by both native and non-native speakers in genuine interactions.

Cheers! 

Rosetta Stone is ok at the very beginning, but it can only do so much.  All 5 levels of French only add up to 50-60 hours worth of language instruction (repetitive drills excluded).  However, estimates are that native English speakers require roughly 700 hours of instruction/study in order to develop a working ability in French.  So when all is said and done, RS will amount to less than 10% of what a student does to achieve semi-decent proficiency in French.   The bigger strategic question to me is after completing Rosetta Stone in the first couple of months, what is done for the following 8 months to solidfy that French?