Moderators have the same powers as I, the owner of this site, have. They are able to lock, delete, move and rename topics. They can also delete or edit any replies, not just their own and without a time limit.
However, they are not able to delete members, make new moderators or edit static pages.
Participate in topics with clear, long, well written replies and have knowledge in owning hamsters.
The best way to recieve help is to post a forum topic about your problem. There, any member can reply and help you out.
But if you want to communicate to a moderator personally, either post a comment on their profile or send them a private message (in the 'Actions' section under their avatar on their profile).