If the DB was in full recovery, and you still have the log file, and you can 'hack attach' the remaining files to a SQL instance of the same version, then you should be able to take a tail log backup (BACKUP LOG ... WITH NO_TRUNCATE)
What part are you struggling with?
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability