Seeders are the people who have the entire file and are uploading it. Peers are people like you who are downloading the file, so they only have pieces of it, but they are uploading the pieces that they do have. So, if there are no seeders and no peers, you won't be able to download at all. If there are some peers but no seeders, you won't be able to download any more than what the other peers have. You can try going to the website where you got the torrent and asking people (nicely) to seed, but you probably won't have much luck with that. You might as well just try another torrent.