Data Recovery After Accidental Delete?

My Packard-Bell iMedia D2525uk running 64 bit Win7 comes as standard with 2 partitions, the C and the Data D. However, by default all stuff created is saved in a series of Libraries which is on the C partition.Over the year or so I've owned the machine I've saved nearly all my stuff on the Data D partition, for obvious safety reasons! but noted that it seemed to be duplicated in the Libraries series of folders. In an attempt to prune the mass of duplicate folders I started backing them up and then deleting.However, I made a mistake and, being presented with a dialogue box giving me a choice whether to permanently delete a folder too big to go in the recycle bin, I did so. The folder was on the Data D partition so I thought it wouldn't affect the duplicate one in the Libraries series, but it did and now I've lost all my documents.