The short answer - you will not make much progress with only one weekly session.
The solution - BUT, if you take your weekly lesson and then immerse yourself in English daily, you can attain dramatic results !
I always supply lots of material and encourage my students to ask for more ! For my students, every day is English day, all my students are welcome to contact me daily on skype, not just on lesson days ! If I am free we have a short chat, if I am teaching they leave me an audio message, either way there is daily speech practice !