What has happend in the short time you have driven is a small wear of the clutch disc. This allows the diaphram fingers to relax a little in an attempt to maintain clamping force, the fingers move (toward the rear of the car) away from the flywheel, forcing the release lever rearward also, until it contacts the opening in the bellhousing. You may be able to purchase a shorter pivot stud that will pull the far side of the lever rearward and the other end (picture end) forward. The one you have may be adjustable, (threaded) and allow it to be shortened.
http://www.thefind.com/cars/info-clutch-fork-pivot