Extremely slow uploading speed

Hello,
I'm in the middle of uploading a videofile but so far the uploading speed has been very very slow. I've tried multiple times over the past few days, starting at about 9AM only to find the file close to 80 or 90% uploaded by about 11PM. I tried uploading a smaller file, which did complete, only to find the "Uploading has failed" error. That was with Firefox, so I'm trying to upload it with IE now.

The file I'm trying to upload is about 129MB large, 4 minutes long and in .avi format (rendered with XVid).

Anyone know if there's something I can do to speed it up? Other sites like Youtube or Warcraftmovies are way faster, so I don't think it's my internet connection :S
Thanks in advance