Jackie: I can recall hearing 'off of' in American films, but I must admit I was surprised to see it used in a 'literary' novel (Barbara Hodgson: The sensualist). I found a second occurrence before I finished the book today:

"She wiped the port off of her nose with her sleeve." [No, you don't need to know the context!]

I also picked up the use of a redundant 'a' in:

"How did he get a hold of it?" [Again, don't worry about the context!]

The usages just seemed out of place to me. But I still enjoyed the book and recommend its quirkiness to readers.