72 HOURS FREE VISA

in february 2013 i will arrive from hong kong in hogqiao airport, shanghai. within 72 hours i depart from pu dong airport to new york. i'm usa citizen. i will stay in the hotel for 2 nights.
am i allowed for free transit visa, or i have to arrive in pu dong and depart also from pu dong? none of official chinese government cites did not published this regulation yet. when it will be published?