1) Create a new simple project with Android Studio.
2) Find the gradle folder in the newproject.
3) Use the export option in eclipse to create the build.gradlescript. (Requires latest sdk)
4) Copy the gradle folder into the project youwant to export to Android Studio.
5) Now try to import this project, u shall be able to select thewrapper check box.
This may resolve the problem you asked for, you can also set theGradle home path and use the other option just fine.
Hope this helps!
http://stackoverflow.com/questions/16891062/android-studio-use-gradle-wrapper-grayed-out?rq=1