If you and your husband want to take a class together, I would highly recommend you work with a private tutor. I looked at several institutes when I first moved here (and did a week long "intensive" class at one of them), but I found it incredibly frustrating to waste much of the class waiting for 20 year olds to arrive late to class with their daily hangover, the inevitable "coffee break" that stretches on for 45 minutes, etc. I just wanted to get in, study like crazy, and get on with my day.
That said, my tutor has been amazing. I cannot believe how much I've learned, and my Argentine friends are constantly commenting on how much my Spanish has improved. Anyway, her name is Adriana, and she works out of her apartment in Recoleta. I know she has students in the late afternoons and evenings. Her number is 4814-0792. Her fees are extremely reasonable, and she speaks perfect English as well.
Best of luck!