I created the following Application for Windows 8.1:

YouTube TOP 25 Most viewed videos app for Windows in the Windows Store

My problem is:

In this application it is possible to watch youtube videos , so I like to store the ID of the videos have watched , my solution was to store a list in the ApplicationData, but there comes a moment of an error due to the space.

Is there any way to increase the space of ApplicationData?
What would be a better alternative ?

Thanks a lot.