This is probably too late...just saw your message...
RE:Assistant Language Teaching:
The British Council has a manual on that with some good ideas...
pdf/whole_manual.pdf
Main site:
www.britishcouncil.org/languageassistant/index.html
RE:Motivation differences:
I have problems here myself...I've worked in private langauge schools in New Zealand so far and have now come to a Japanese high school and the difference is herrific! The private school students were highly motivated, I think because they had English all around them in NZ and needed it every day, supermarket, shopping, school, and they were studying full-time too, that's why they were there...and they were a couple of years older than my students here...
In Japan, I have students not even wanting to talk to me, partly out of shyness, but there seems to be a "Why should I learn English" attitude, and some have their heads on their desks!! I think the emphasis society puts on learning languages can make a difference, the environment in which they learn, and their own personal reasons for which to learn...these are all things which influence motivation I think...but maybe here it's also just being a teenager...we all know what school was like then for most people...
Don't know if this was the kind of stuff you needed?
Hope the presentation goes well!