Your best bet will be to get them from a manufacturer located at the source; Hawaii. Many Hawaiian manufacturers offer their coffee in both roasted and unroasted form.
There are options available when you are looking to purchase coffee beans. Your best approach is to go to a good coffee shop, as they would carry what you need.
If you live near large food retailers like Whole Foods you might try them. However if you have no store close or they don't sell them check online. Website like konacomfort. com and alibaba. com sell unroasted beans but search for other if you like.
You can find them for sale where they are grown - in Hawaii! If that is a little far for you to travel, try searching on the internet. They should be available for online purchase.
Typing in the words unroasted Kona coffee beans into a search site such as Google will help you locate numerous shopping sites in which you can purchase from. Two locations I found were KonaComfort which offers organic unroasted beans; and Amazon which has Green Kona beans in 1 lb packages.