[CentOS] Bandwidth issues

Hello this is the first time I write to the list.

I use in my company CentOS 5.5 on all servers, especially in the firewall, recently I have problems with bandwidth, since my internet connection is 512 Kbps and the same is saturated with torrents.

I need to limit the bandwidth consumption for torrents, giving highest priority to http traffic. leaving the torrents that are downloaded from a single IP address at a speed of 128 Kbps

I use iptables on the firewall.

Could tell me if it possible to limit such traffic with iptables and send me some examples?

Thanks

Michel