I don't think you can....
I'd also be interested if I'm proved wrong
bandwidth monitor pro , or net meter (a freebie) will show your lan transfer rates .... but the actual dsl speeds happen "outside" your lan (for this reason you can't display your wan ip address using ipconfig either)
(ip2 from
http://keir.net will test and show your wan ip at that time)
There are websites that will test the speed (you can't use your connection while the tests are running)
.... and some routers will show the negotiation speed (dunno 'bout yours ). but they are all snapshots not realtime