For each attribute you have you need to call:
$product->setData('attribute_code_here', 'Value here');
[Edit]
For yes/no attributes do it like this:
$product->setData('attribute_code_here', 1); //1 for Yes, 0 for No
For multiple selects
$product->setData('attribute_code_here', "4,6,12"); //the ids of the values concatenated by comma.