First, I recomend you to place your questions in Moodle in Spanish (Moodle en Español), the community that uses Moodle in Spain and Latin America is very big and you can benefit from their expertise. Or, you can post the same question in the two places . Well, thats my opinion. Try the forum for Teaching strategies or the forum in Moodle in Spanish: Cosas de profesores.
For the questionnaires you want to design with your student, remember that if the questionnaire is not already designed, you can do it so with the questionnaire module. You can leave open questions so your students can feel free to answer what they feel about that subject. And for what to do with them, well, you have to analyze the results with them in a forum so they will take part of all the decisions that come along from this survey. You can divide them into groups and make them to write about this.
An for the power point presentation, Martin is right, with so many students that are ahead of us in technology, you can ask them to help you. I am sure you can find one or two that would do the technical job for you.
And for the amount of students, yes, I think 54 in one classroom is a lot, but you have to rely on groups, forums and collaborative work as wikis. More information? See you in Cosas de profesores.