Enter your Downstream attenuation (dB) .....62.0
Cable Loss (dB/km) – Default 13.81
Attainable Rate (ADSL1) – kbit/s.....2133
Attainable Rate (ADSL2) – kbit/s.....2141
Distance to exchange (Meters).....4490
Judging by your attenuation you're approx 4.5 km from the exchange in terms of cable length. Downloading at 256 KBps is roughly 2.048 mbps so your speeds are pretty much bang on what you would expect to be getting. Essentially there's nothing that can be done to improve that