You have iLife '09. iLife '11 also works with Snow Leopard, but if you install it and use Software Update to update iMovie and iPhoto, you will see that they won't be updated to iPhoto 9.4.2 and iMovie 9.0.8.
These versions require OS X Lion or Mountain Lion, so they won't work under Snow Leopard. However, your Mac won't allow you to install those updates
If I understand you correctly, I can get the most advanced versions of iMovie and iPhoto in iLife 11. Furthermore, there is no danger of updating to the point that they will no longer be compatible with Snow Leopard. If I had known that before,I could have saved myself a great deal of trouble, and I could have done it long ago. Well, live and learn.