Ideas, tools, frameworks to extract ( user, questions, answers) from different online forums? [on hold]

I am good in java. But R, Python is completely new for me. Moreover, this is my graduation project and have limited time left of 3 months. Please suggest me the best way that i can implement fast :

-download forums q & a data for X months (extract user, question , answers )

-do clustering analysis (categorize by topics, most contributors, high scored answers....).

I started by implementing a simple web crawler, but the HTML tag for q & a data changes for each forum /=.

Thanks !!!