I'm have studing french from past 3-4 months, at Alliance Fracaise Toronto.
So far, I have completed A1 and learning A2 for 2 months now.
Before, my plans were to give TEF after 6 months of studying French, but now I'm looking at 1 year and 3-4 months. My teacher gave TEF for immigration and she recommeded at least complete B2 level.
FYI, I study 2 evening classes each week and I also study via Rosseta Stone at home. From my personal experience, you would need 1 year of full dedicarion, before you can score good in TEF. Choice is yours!