How can i transfer emailaddresses from my dropdownlist to my contacts OR where can i find the emailaddresses that are shown in the dropdown list when creating an email
If you are asking about addresses that are automatically collected from those you enter manually, you can find a list at Menu > Tools > Settings > Mail > Compose > Recipients History > Show Recipients. You can right-click on each one individually and save them to your address book.
Unfortunately, there is no way to do them all at once. ;-(