Chris,
You can install plugins in MyEclispe 2013 using “Install from site” under Help menu. Go to Help > Install from site > Click on “Add” button > Give some name and click on “Archive” button and select the plugin zip file and click “Ok” > Select the plugins you want to install and click on “Next” and follow the wizard to install the plugin.
Alternatively, you can install plugins using dropins method. Extract the zip file to <MyEclispe installation directory>/dropins folder > Restart MyEclipse > Upon startup, MyEclipse will automatically check the dropins folder, add any plug-ins it finds there, and report the status of the additional plug-ins with a dialog.
Let us know how this works for you.