Good points Mahood, and made me think of another thing. A lot of times, deleting a photo in iPhoto doesn't actually delete it from the hard drive, but only removes it from the iPhoto program itself.
Try going into your user file, then Pictures. Right-click on iPhoto Library and select Show Package Contents. In the file that opens, look for a folder called Originals. Inside that folder, with any luck, will be a different folder from each year (and different folders for each day you uploaded a photo within those). Inside these folders should be the original photos, as they were when you first uploaded them.
Good luck.