If the dish etc has been in place for six years there could be any number of reasons why the signal has only just started deteriorating.  The dish could have moved a bit, the cable and/or the LNB might have gone down and also it might be an idea to rescan your channels from time to time as there has been some reallocation of transponders on the satellite itself.  If I were in your position, I would consider replacing the dish with a 1.2, with new cable and LNB and of course get the dish and LNB correctly aligned.  I'm considering going from a 1m to a 1.2m myself.