Forget the Rosetta stone and all the other stilted tapes unless you are a rank beginner. Actually, the way you were doing it (increasing comprehension thru listening to podcasts, TV, etc.) is THE way to go and you can will be fluent as a speaker once you understand most of what you hear (automatic). There is an excellent News TV internet site in BsAs
http://www.tn.com.ar/
as well as a great Tango radio station with hundreds of podcasts about tango music in Spanish.
http://www.tangocitytour.com.ar/
If you've had a couple of years of classroom Spanish and can tell a noun from a verb, I would begin there. It will be difficult at first (very) but in a couple of weeks of listening for an hour a day, you will be suprised. Don't try to translate into English..instead just try to 'get it' in Spanish..you will be fluent in 5 mos. to a year if you listen for an hour a day. Most people won't put out the effort. Try having a BsAs radio station playing when you are on the internet..just background chat and music..
http://www.radiodelaciudad.gov.ar/
This one is a government radio station but a good one.
You have to be able to withstand some initial confusion at first and then hang in there in order to get the language. You will need a year's work in the classroom or with a tutor to be able to begin this. But this approach will then get you fluent in 5 months from your own home computer. Just remember the required one (or more) hour a day. Let me know if you decide to do it and have any questions.