Hello,
Please share website address where in we have to fix Google map API. Yes we not need any upfront payment just you need to create Milestone and once project done you can release payment.
Check our 200+ positive reviews at http://www.freelancer.com/u/jkphugat.html and portfolio. We are open to respond on your questions/suggestions before you award project.
I will be waiting for your response and we are interested to work with you.
Thank you,
In kindness - Jitender Singh