Charles Oscar Klust b: 1830 Hirschberg

Researching the Klust family. I have them from 1857 onwards in London England. Charles/Carl/Oscar/Oskar Klust/Kleist married Isabella Harding in 1857, I have them and the family on the 1851, 71 and 81 Uk census. Would like to obtain birth certificates and details on immigration but have very little knowledge on how to do this. Any help would be greatly appreciated. Was Hirschberg East or West Preussen in 1830 ?? Many Thanks should read 1861, 71 and 81 census