ask immediatelly in your emabssy / consulate what papers are required and how long takes their processing
register for the Conference and pay the conference fee
write us (eamt08 at informatik dot uni-hamburg dot de )
exactly what kind of paper do you need, what information should be in the invitation (some embassies require e.g. passport number, date of birth of the applicant etc; you may give us then these informations)