Virtual assistant needed to promote service on blogs, social networks

I need a virtual assistant to promote my service on blogs and social networks.
The candidate has to write good in English and should write/comment on famous blogs and social networks about my product.
The candidate has ho have a working facebook and Pinterest account and has to be familiar with facebook group posting, Pinteresta nd blog commenting.

I will provide some links og groups and blogs where to comment but the candidate will have to research it too.