I'm not sure how you equate the Task Manager, (Networks tab?), with your DSL ISP connection speed.
I don't know DSL, but with broadband your connection depends on the package you have purchased with your ISP; eg, you join up for a 1Mbps service and you get 1Mbps, or you sign up for a 10Mbps service, and you get 10Mbps.
Of course, downloads may not always be at the speed you have signed up for. Internet traffic, broadband capacity etc may affect downloads, and uploads will nearly always be slower.
However if you have signed up for a service with greater than 1Mbps and you are only getting 1Mbps, then you could get a speed check done online, one of the favorites is;
Also, you could confirm with your ISP what speed you should be getting.
How can I increment my downloading speed with DSL? I'm at 1Mbps out of 100Mbps that the task manager shows.