If you would like to use the AdWords API to pull historic stats, you could use the report types listed
here and specify the appropriate date range. In terms of limitations, the size of data set that can be handled in one report call while dealing with historic data is something that needs to be considered. If you face any issues while making the AdWords API calls directly, you could post those questions in this forum.
Thanks,
Sreelakshmi, AdWords API Team