ADSL Problem

Hi everybody We have a 512/256 ADSL connection with suse 7.2, we used yast 2 for installing it and point to the network card eth0, everything looks fine, the problem we have is that for downloading instead of 512 kbps we get 100 kbps for uploading it is fine, we thought it was the line so connected it to a M$ w2k machine and we got the 512, does anybody know where can i get information on this?. Thanks to all for your patience with this newbie question