In our installation of the moodle system we decided to create a new module to work in conjunction with the quiz module to upload a file containing prepared multiple choice questions.
The import section being introduced in the moodle quiz module in the CVs seem to be the adapted approach for moodle. However in our system we did manage to upload a file and insert the questions in to the relevant databases so the questions were available in the course. We also facilitated the insertion of images for the first 10 questions.
We used a file originally based on the index.php and mimetypes.php file in moodle/files directory to upload and select the required files from the PC, and then a file called readfile.php to split up and insert the question details.
I am attaching our code we are using in the hope that it will help with the development of the new import function in the quiz module. It may take a bit of work to integrate to your own system but the basic functionality is there.
I have also included the format for the quiz files accepted by our system. We have made some changes from the format; the course code is not now needed.
Paul