First of all, you don't construct an array with a new keyword. Just $var = array($var1, $var2);
Second, if you wish to go the array route, then just extract the array's element using $content[0] and $content[1] (You change change that var name)
Lastly, you could always just add another parameter to the function new_todo($content, $author) and then call that function with the same arguments.
Hope it makes sense!