Unable to import 'facebook' sdk 4.9.0 as module in android studio 1.2

I get 'Specify location of the gradle or android eclipse project'. I followed the following steps:

1) Added mavenCentral and dependency in app->build.gradle as

 apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.example.akshitag.cooltrends"
        minSdkVersion 15
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

repositories {
    mavenCentral()
}


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.1.1'
    compile 'com.facebook.android:facebook-android-sdk:4.+'
}

2) Build the project which is successful.

3) Download and Unzip facebook sdk. Use Import Module under File->New and select facebook folder. Inside the unzipeed older, I have this: \facebook-android-sdk-4.9.0\facebook-android-sdk-4.9.0. It contains AudienceNetwork and facebook folder. Inside facebook folder, I have following files: sample, facebook-android-sdk-4.9.0.aar, licence.txt and notice.txt

Also, this is how my project structure looks like.

Could anyone guide me here please?

You already compiled sdk in gradle then why you want to add it again using different method ? Your project is done, you don't need to add it as a separate module.