I take it you've tried the Resend Password link?
One way round this involves you accessing your database directly either through your host's control panel options or by using phpMyAdmin which you would probably need to upload to your server.
The next step is to access the table holding the admin settings (probably zen_admin, or could be just admin) and change the admin email address to a valid one for yourself, then return to the admin login page and use the Resend Password.
If the above is meaningless to you, then you need to get someone else to do it for you. You will need to supply (NOT IN OPEN FORUM :wink:) either host control panel login or FTP login details - and be aware that if it has to be done via FTP then it is going to take up some of their time as phpMyAdmin would need to be uploaded and configured)