I have fixed minor corruption in a database where the required information was in the logfiles. You can try to do a manual database recovery and point to the log files when it asks for the rollback. If you have enough rollback in the log files you might be ok. Your database might not be as bad off as you think. Before you do a lot of experimenting a backup might be a good idea. Are you in archivelog mode? I guess after this experience you will be looking at daily exports and daily full backups as well as archivelog mode. You might also need to issue a recover statement against the affected datafile.

Good Luck.