james-wrx

guys im in a bit of a panic I have got a very bad judder when pulling away and it's even worse when changing down and lifting up the clutch again, it's a very violent judder/banging that shakes the whole car, also the biting point seems a bit lower than before, the fluid hasnt been changed in a couple of years (minimum) would this give these symptoms?
Bearing in mind the hot weather and the location of the clutch fluid I have had judder from sitting in traffic befor but not as bad as this!
Any ideas would be greatly appreciated!
How do you bleed the clutch/change the fluid?