http://tweetfull.com is the tool.
From the site
"Let us assume you work for Apple. Hypothetically speaking, you want to engage with people who love Apple or hate ..say.. Samsung.
You can easily setup a promotion for that. Our intelligence engine then analyzes and favorites and/or Retweets relevant Tweets using YOUR Twitter handle.
The Tweets you engage with will bring those people to you and then you can convert them into customers. How do you like them apples?"
Works pretty good.