Try d/loading a file from this site:
+ MagnetMix.com +: The Source for Good Content. Just click the d/load link and it'll send the file to LW. You should get decent d/load speeds. If not that could mean that your isp is shaping your bandwidth.
Try d/ling a couple and post what speeds you get. Sometimes it takes a little before the file starts d/ling, so give it a few minutes to get going.
If you haven't already, you could try portforwarding your router:
Port Forwarding for the Netgear WGT624v3