thank you shiyie for giving it a try,
You need to replace all the files provided with the theme("
http://GitHub.com/harshjv/q2a-bootstrap") with your Q2A Installation.
You don't have to place this files in qa-plugin folder.
Just replace the whole installation with theme files.
Then, go to admin->general and apply q2a-bootstrap theme.
******************* important***********
Make sure, you have a BACKUP of whole Q2A installation before proceed with theme installation.
***** for more info, please visit GitHub project******