You can add a magnet link or a .torrent file from your computer, check out this tutorial on the How it Works page
Normally torrents with few seeds download slowly. Seeds are how many people are sharing that torrent to enable you to download. If the number of seeds is low, there is nothing we can do.
We recommend to always seek torrents with a lot of seeds, but if that's not possible, you cant leave SuperTorrent to download that torrent for you, little by little.
Unfortunately no. When adding a torrent all files are downloaded, this is because more than one person may be trying to fetch the same torrent file than you, and we use the same download, to save bandwidth and maintain the best service.
You can select any MP4 file into your torrent, and instead of clicking "Download" you can click on the arrow side and then on "Watch Online"
Unfortunately at the moment only MP4 files are accepted because browsers do not reproduce most of the other files, nor with HTML5 or Flash player.
You can buy a larger plan that will not lose days of the current plan. Your current plan will be added to the end.
For example, if you have 5 days remaining of the 50GB plan, and buy plan of 200GB of 1 month, it will be instantly released the 200GB plan, after 1 month, your account will be reduced to 50GB again, during the remaining 5 days.