To my knowledge and judging from many other cases the manufacturer keep a very tight grip on spare parts for lenses and cameras as long as they are in production. Ebay is a possible source.
Another option is our bro fatigue, DIY specialist for cameras and lenses.
A third option could be to get the newer versions of the kit lens: either the one with IS or the newest one with IS and STM focus motor. They both have a better optical quality than the earlier versions.