Hi Dubhgan,
The total filespace available to you on Moodle is 100MB which is also the file upload limit for a single file to this area.
The standard repositories are switched on in our Moodle. Wikimedia is an additional repository that is supported by Moodle. Requests for global changes to Moodle would have to come via an academic on your course programme detailing why it is required. If there is a good academic reason to switch it on then we can investigate but please contact your tutor or course organiser in the first instance.
Wesley