Its not a difficult task there are many ways you can achieve this, I mean many tools and libraries but i recommend you the QT library that is simple and eassy. Just open QT designer make a new wedget and drag some buttons on it and then define an event slot for each button and then save it. The just open it in KDevelope and make the subclass and give the implementation of those slots. To run a script you can you the system command to and execute your script file or there are more ways to do this. Compile Run And Enjoy
Look the combination of QT and Kdevelop is very eassy and simple. I know if you are new to this you may find it confusing, If it is so simply go to kde.org and see the tutorial of QT, just folow some simple steps and learn to make GUI's.