Best for learning Spanish? (Mexico City)

Hi everyone!

I've been in Mexico City (near Santa Fe) for almost 3 months. After having slept thru 2 years of HS Spanish I now need to become proficient in the language. I have been taking private sessions at Berlitz, but am not happy with their system.

I will be traveling until 31 December and upon my return will need to continue with my Spanish studies. I have heard about the CEPE program at UNAM, but it is near Coyoacan and the travel times scare me as it is a 5 day/wk program in the afternoon. But OTOH a class (hopefully) will offer me the opportunity to meet other people.

Does anyone know about CEPE or other programs that can get me up to speed with the language quickly? Would private sessions be better?

Thanks in advance,
Stanton