Try using an undelete utility to get the deleted file/s back. Do it right away, because as soon as new data is written over any part of the the deleted file you won't be able to undelete it. If you can undelete the file/s then you can attach them to get the database back.
If you can't undelete the database file/s then you have lost the database for good.
As snSQL mentioned you have to recover your database other wise there is no other option than restoring from previous backup... If you have no backup then you out of luck...