You escape quotes in javascript with the backslash:
,{v:'<A onclick="window.open(\'popup.html\', \'windowname1\', \'width=200, height=77\'); return false;" target=#>click here</A>'}
You might be better served using the selection event handler to do what you want though. After drawing your table (assuming you named your viz table object "myTable"), call this:
google.visualization.events.addListener(myTable, 'select', function () {
window.open("popup.html", "windowname1", "width=200, height=77");
});