Welcome ,I will give a full and clear answer to your question, please make sure to reply to any questions I have. They may be essential to my reply.
Hi If you want to Use imovie HD you still can but not for import .
Import your footage using imovie 11
then , Go to the project , you can right click on the project file . Show package content .
Navigate through the Content folders to find the imported video files .
Copy the files to the desktop as needed and import in the imovie HD .
Does this help.
if your new camera has a memory card , you may also use a USB memory card reader to access the data directly , copy the files to the Mac desktop and import or convert with MPEG stream clip and then import if needed .