Utorrent speeds have suddenly dropped to a crawl

[liferasta]

hi, Over the past week I have found that my download speeds have dropped off suddenly, for example i am downloading a torrent with 83.999 availability with 89(2267) seeds 11(1141) peers & it will not go above 40KB/s, I am on TalkTalk Isp download 7073 kbps (884kB/s) upload 878 kbps (110kB/s) & I have correctly forwarded a port on my linksys wag160n router with a green tick in Utorrent & allowed it through my windows firewall running Vista 32bit, Details of the settings:

Connection:

Port: 55641

Enable UPnP port: unticked

Randomize Port: unticked

Enable Nat-PMP Port Mapping: ticked

Add Windows Firewall Exception: ticked

proxy server: none

Bandwidth:

Download Rate: 0 (unlimited)

Upload Rate: 70

# of connections global: 450

# of connected peers per torrent: 100

# of upload slots per torrent: 5

Bitorrent:

Dht: ticked

Dht for new torrents: ticked

Peer discovery: ticked

Ask tracker for scrape: ticked

Limit bandwidth: unticked

Queueing:

maximum active torrents: 20

active downloads: 10

Seed While:

Ratio is: 150 / seeding time 0

Seeding tasks priority: unticked

limit Upload Rate: 70

Web UI: unticked