First, is it possible to connect your laptop up to the homehub with your cable to do a speed check. This will cross out any problems with the ISP end of your system.
Then do a speed check with any free speed check sites (do a google) which you can find.
I had a similar problem and I used a site called
click here to reset my TCP options. I am not saying you have to go that route, but it sorted mine out ok. I went from 2mbt to over 7 after I used it.
hope this helps you.