OK, line attenuation, the lower the better e.g. if you lived nextdoor to the exchange your attenuation would be 1db. 35 isn't bad and in theory you should be able to get the maximum 8 Meg connection speed with that *
Noise margin, if you connect at less than the full 8 Meg then 6 is the optimum figure. Yours is 5.7db which is near enough. Keep an eye on it though as you don't want it to drop much lower or you will lose sync.
* As you aren't getting the maximumn potential speed from your line I would check your internal wiring. Are you connecting through the first socket in your house, the master socket? Follow the guide
click here and check if the ring wire is connected. Removing this can often result in improved speeds.