Personally, this is more the type of groups I work with everyday and I don �t use a book at all. They just want to speak, so I suggest approaching it from another point of view (hard to do if you have taught in the traditional way for a while):
Grammar is NOT that important!
Speaking and being understood IS important.
Mistakes are okay--as long as they don �t change the meaning or prevent understanding
They don�t have to speak perfect English, they only have to understand and be understood
For these types of groups I:
Use LOTS of conversation exercises and games
Explain grammar in detail only when the mistake keeps repeating and affects understanding
Build my lessons in such a way that almost the entire lesson is primarily conversation
Correct mistakes as they speak, but am not pedantic
(Just my opinion, but seems to work well for me.)
There are LOTS of great worksheets and games on ESLP that support this teaching method.
Douglas