if the torrent is yellow, you need to open ports in your firewall (both software firewall and hardware if you have a router). try using non-standard ports in the setup of your BT client, some ISPs are now blocking default BT ports to save their traffic, just choose a random lot of 10 somewhere like 7000 or 18000 or whatever
set your max upload speed to a few kb/sec less than your connection's max upload. i find it works best when you can still *just* surf the web comfortably whilst max uploading
unless a torrent has over 10 seeds it's bound to be pretty slow, especially if there's like 2 or 3 seeds and about 150 people downloading like most popular stuff (playstation isos, divx movies, etc)
to test your setup, try downloading from a popular, well seeded torrent such as a linux iso, it should run at full speed up and down