That version is running around on the right wing web sites, for instance here:
http://campaignspot.nationalreview.com/post/q=MDg1MTk0YjQ2YjI1ZDBhNDYzMTA4Y2NhMDA4ZWRlOWU=
However, it appears to be an intentional misquote, dropping two key words and applying the most inflammatory possible punctuation. What he actually said (at least, this is how it sounds to me, and there is an audio link here too)
http://www.huffingtonpost.com/taylor-marsh/obama-grandmother-typic_b_92601.html
was:
Ignore the punctuation, he was clearly putting the sentence together as he spoke it (hence the "uh" pause). I believe the construct was intended to be:
she is a typical (white person who if she ...).
Here is a shorter equivalent construct without the racial tension thrown in to muddy sentiments:
He is a typical dog who is afraid of the rain. Most dogs are not afraid of the rain. The sentence says that those dogs who
are afraid of the rain share a set of behaviors or other characteristics, and the particular dog that is referred to belongs in that restricted group.
Had he to do it over again Obama would most likely have avoided the word "typical", that always rubs people the wrong way. That pales in comparison to the quotes which drop the "who" and "uh" so that a period could be placed after "white person", converting what was supposed to be a nuanced classification of people like his grandmother into a broad categorization of white people in general. He clearly included "who" in the preceding phrase, but the misquote could hardly have ended the sentence with ".... typical white people who." So they had to drop the who in order to mangle the meaning. To borrow a phrase:
typical.
Sometimes English sucks for communication, especially in cases where punctuation would change the sense of a sentence, and when it is spoken, one cannot always infer the intended punctuation. See Lynne Truss's book "Eats, Shoots & Leaves" for innumerable examples of what happens when punctuation is misapplied.