These drop in drop out problems are often caused by line issues whic can be caused by other devices interfering, being too far from the exchange to support ADSL2, having something wrong with the phone lines (they may be good enough for voice, but fail with ADSL/ADSL2) or a combination.
Try disconnecting your phone (and filter) from the socket and see how it travels as the only device connected your phone lines at home.
If you are in ADSL2 mode, try configuring the modem and dropping back to ADSL1 - I've had to do this at home to get my connection stable - although I do still connect at 6000kbps.
If you like IE 7, Download Firefox3 and give it a go