google_play_services-lib is installed using the Android SDK manager. It is under the extras section called "Google Play Services".
You really should try not to use the google_play_services-lib any longer if you can avoid it. It contains the entire client library for google play services which is very large, and in most cases, your application is only using a small portion of the client SDK.
jar xf You can find them in the extras/google/m2repository directory, broken down by package name. In the same directory as the .aar file, there is a .pom file which is an XML file. At the end of that file there is a list of dependencies - you'll need to expand those as well.
This way you will have only the smallest set of dependencies for your app.