Well, those figures are basically rubbish.
From what you say, you have a fixed-rate ADSL connection of 1Mbps, your sync speed will be 1152kbps (dredging memory). If so, you should be looking for d/l speeds of around 960kbps, upload around 26kbps (again, dredging memory).
Who is your ISP?
Speedtests do vary tremendously throughout the day. At peak times, they will drop. If I wanted to benchmark my system, I'd probably do it around 5am to see the maximum that could be obtained, and to reduce the chance of contention or server load being a factor in the result.
It would be worth trying the BT tester
here, but be patient with it, again 5am is a good time.
Can you get to your line stats? If so, post them here, people will be able to advise you if there's anything you need to sort out.