Shaders can be daunting at first, but I would hope it would not take weeks of your time to come up with what you need. The amount of programming for even a relatively complex shader can be done in minutes once you are familiar with AGAL. The rest of the shader is boilerplate you can copy and paste from existing shaders.
It can take time to learn AGAL and become familiar with how to use it within Starling, but again hopefully not weeks. For what you want you need a filter, which you make by subclassing FragmentFilter. There are a number of these in Starling you can use as a starting point, as well as more available as extensions. There is a section in the manual. If you run into problems just ask here.