Currently your site is violating the terms of google map usage. you can not ask them to allow you to keep on violating their terms.<p>The better solution would be to write them the letter to allow you to implement the functionality of your own with in some specific time period (may be 1 month)<p>Then, Create your own solution on some open standards or tech 
I recommend you to use openstreetmap mbtiles(<a href="http:&#x2F;&#x2F;wiki.openstreetmap.org&#x2F;wiki&#x2F;MBTiles" rel="nofollow">http:&#x2F;&#x2F;wiki.openstreetmap.org&#x2F;wiki&#x2F;MBTiles</a>)
I have worked with them, they are tricky but really great.