The speed at which you download is determined by things such as the Seed to Peer ratio, the seed(ers) upload bandwidth and of course your available download bandwidth. Try to download torrents that have lots of seeders and/or fewer peers in order to get faster speeds.
Also make sure you have forwarded your ports correctly [1, 2].
1 -
http://antsmarching.org/forum/showthread.php?t=182995
2 -
http://antsmarching.org/forum/showthread.php?t=182994