SKY CONNECTION ISSUES

As a not tech "silver surfer" I would appreciate any help possible on my issue of varying connection issues :
I am on SKY Unlimited B/B with a Sagecom F@ST2504n router :- Connection Speed
11257kbps Down and 1094kbps upstream : Line Attenuation - 35dB Down 20.8 up
Noise Margin 5.9 dB Down 7.9 dB up.
Think Broadband speed check shows an average down load speed of around 9Mb and an upload speed of 0.9Mb can I expect any better from these stats?

I downloaded the TB Quality Monitor and have noted that SKY IP address has changed 3 times in the pat 8 days whereas it had not changed in the 4 weeks before that.
Details of the results for 1/4/20013 on Sky's previous IP address
http://www.thinkbroadband.com/ping/share/2bdebe608e2...
and for the IP address for 4/4/2013 is at
http://www.thinkbroadband.com/ping/share/f597bfdfe1a...
Nothing in my setup has changed and SKY say that everything is working fine with no explanation for the changing IP address.
Thanks in advance

Estimate from http://www.coolwebhome.co.uk/calc/calculator.php?par...

Pretty spot on the money, some people might be able to go faster on the sync speed but only a little more. While Sky does not have the IP Profile there are still overheads so losing a Meg of sync speed or so at the speeds you have is not unreasonable.

The IP addresses may be nothing, Sky use dynamic IP addressing so if router reboots/resyncs a good chance it may get a new IP address