The below line in the .js file is where you should insert your API key:
script.src = 'https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false&key=1234567890'
However when I tried that yeterday it did not work. It did work if I use the stand-alone code below just inserted in the page where you need the map to appear, although I have no idea if there will be a conflict with what is in the js file.
<script src="http://maps.googleapis.com/maps/api/js?key=1234567890"></script>
<script>
var myCenter=new google.maps.LatLng(35.0804922, -78.9648236);
function initialize()
{
var mapOptions = {
center: myCenter,
zoom:16
};
var map=new google.maps.Map(document.getElementById("map-canvas"),mapOptions);}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
<div class="templatemo-contact-map" id="map-canvas"> </div>