i have a box connected to the internet right now: gigahurts.net
it downloads at speeds up to 20kb/s and uploads at 1MB/sec (on campus) or so.
in situations like these, i suspect a hardware problem somewhere. try using a different cable. if that doesnt work, try a different network card. since you dont have anything to really test it with (we have Fluke nettools) you'll have to just swap stuff out until it works.
to test software issues, try uploading to a different computer, try downloading from a computer, try as many different scenarios as possible to see what is slow and what isnt.
kill all unecessary processes and firewalls also (on all machines in the mix) and see if that makes a difference.