You can now see your ad extensions performance separately within AdWords:
In order to help you manage and track the ad extensions in your campaigns, today we’re introducing a new Ad Extensions tab within your AdWords account. From the Ad Extensions tab, you can see statistics for any of your campaign ad extensions. You can choose to see "All" or "All but deleted" extensions, and you can also choose the type of ad extensions to view, such as location or product extensions. For example, if you select “Locations,” the tab will display all location extensions for that campaign (on the campaign details page) or all campaigns (in the “All Online Campaigns” overview).