Dreadful internet connection

[#1]

In the last week or so my connection is become dreadful. I can no longer play online at all becuase of disconnection errors and very slow speeds.
I checked speedtester and only got 699Kbps. Last time I checked I got 6Mbps -  ten times faster!
My profile is set to 6000k.

Test1 comprises of Best Effort Test:  -provides background information.
Download  Speed
699 Kbps

0 Kbps 7150 Kbps
Max Achievable Speed
Download speedachieved during the test was - 699 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :7616 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 6500 Kbps

My router reports:
ADSL Link Downstream Upstream
Connection Speed 7616 kbps 448 kbps
Line Attenuation 18.0 db 11.0 db
Noise Margin 13.9 db 22.0 db
Please can you help me, because if this is not fixed soon it will ruin my Xmas:(

[#2]

Have you recently changed any microfilters or plugged anything different into your telephone sockets such as a sky box or anything?
Try rebooting your router?

[#3]

Hi batfink,
Did you get this resolved or are you still having problems?