ADSL - but slower than 56Kb modem

This is very annoying. I have an ADSL connection running now from China Telecom, but the connection speed seems not nearly close to the 512Kb I am paying for. Downloading speed typically reaches an average of 4Kb!! This is clearly insufficient.
Also connection test websites show me that my connection speed is very low: with around 40kb higher than the actual download speed, but still very low. I wonder whether it depends on where I am downloading from. Perhaps I should check downloading from some Chinese sites to see which speed I reach there. Although, with my limited knowledge of Chinese, this is easier said than done.