Google Map loading slowly

On our new site (still on development host) we have a Google map with 100+’pins’ and the map takes quite a while to load. I’ve asked friends to check for me on their computers and different browsers.
This will have a negative impact on new visitors when we go live with it. Is there a way to speed it up? http://adgdev.info/fortunate/ We don’t have W3 Cache plugin installed if that’s a factor.
thanks.