This "You are attacking a literal interpretation of the Bible" is a common challenge thrown up by Christians/believers and atheists alike.
When an atheist brings it up it is usually to mention why a particular argument they are reading about wouldn't work.
When believers talk, you often hear some kind of appeal to a more nuanced and suble faith that have that is somehow more sophisticated than the fundamentalist Bible believer.
Don't allow a person to say such things without being pressed to be more specific.
I just posted a new article: Response to: You are attacking a literal interpretation...
It gives you questions and more importantly a mindset to really dig in and find out what a person means when they say such "nuanced" things...
The article also involves a new tactic which emphasizes good information flow between people in a conversation -- not a tactical gambit to 'win'.
Let me know what you think!