Ok... After doing a hard search, the following two sites are the only ones I could come up with: www.amberjewelry.com  <--- Here, if you cannot find what you are looking for, I would email them as they may be able to special order something for you.  I checked them out and they appear to be reputable. 

The  next site is: http://www.shoppoland.com/amber_and_silver_jewelry/

Now with this site, it has a lot of Poland-based shops.  I didn't go through their list as it has a lot to choose from, so take your time and check them out.  I wish I could be of more help to you.  I will continue to look and if I find anything different I will post that as well.  Good luck to you.