Is there an API or a way to get the GPS location of a certain address ?
I have to loop through a list and get the GPS longitude and latitude.
What you are looking for is called Geocoding
Geocoding is the process of converting addresses (like "1600 Amphitheatre Parkway, Mountain View, CA") into geographic coordinates (like latitude 37.423021 and longitude -122.083739)
You can use Google Geocoding Service for this.