how could I find out the problem source on broadband connection?

hey all, my connection is 10mbit VDSL line, during these two months, my upload speed to EU and US are very damn slow, average speed is around 7KBytes/sec, does anyone feel free to try to find out what's going on ? at first, I was suspect that problem might caused by GBLX, but after one of the engineer check the link, it seems not related with them, so I would like you guys to help a bit, please try to see what's going on, let me know if you found anything, I got a server for you guys for download a sample file so that you could track down the packet routing path: http://sml.dyndns.org/files/testmusic.mp3 Thans a lot all