iphoto lost on backup?

I am a professional photographer, but not much of a computer person. I have a Mac OS X - 10.6.8 I moved many of my photos to iphoto while I learned aperture. iphoto wasn't made for the large quantity of photos I had moving on and off - I exported my iphoto library to an external hard drive which I also used for time machine. I then deleted all of my iphoto library from my Mac. I am now trying to import my iphoto library into aperture. However, I do not see any of the iphoto library on the external hard drive...I am in a bit of a panic as I have orders pending. Have I screwed up somehow...any suggestions?