It says on another thread that the release arm can become a little stiff on certain models, and i think the advice was to give the arm a good squirt with some WD40 and leave it soak. I think this would be a good idea as a cheap option before you have to start thinking of a full clutch replacement.
BTW has there been any other signs of the clutch going, slipping, smelling etc?
Oh and did you make sure that the pushrod was inline before you actually used the clutch, they can be a bitch to line up especially if you havent replaced the hydraulics at the same time as the bracket ( the plastic ties are on the new ones for just that reason to keep it all square when you fit it, and then break when the clutch pedal is first pressed) if it wasnt square would be putting a lot of undue pressure in the wrong places.
Hope this all helps, and look to the cheapest and easiest options first..
D