Get all twitter mentions using tweepy for users with Millions of followers

I had a project in mind where I would download all the tweets sent to many celebrities for the last one year and do a sentiment analysis on them and evaluate who had the most positive fans.

Then I discovered that you can at max retrieve twitter mentions for the last 7 days using tweepy/twitter API. I scavenged the net but couldn't find any ways to download tweets for the last one year.

Anyways, I decided to do the project on last 7 days data only and wrote the following code:

try:
        while 1:
            for results in tweepy.Cursor(twitter_api.search, q="@celebrity_handle").items(9999999):
                item = (results.text).encode('utf-8').strip()
                wr.writerow([item,results.created_at]) # write to a csv (tweet, date)

I am using the Cursor search api because the other way to get mentions (the more accurate one) has a limitation of retrieving the last 800 tweets only.

Anyways, after ruing the code oveight, I was able to download only 32K tweets. Around 90% of them were Retweets.

Is there a better more efficient way to get mentions data?

Do keep in mind, that:

1. I want to do this for multiple celebrities. (Famous ones with millions of followers).

   2. I don't care about retweets.

   3. They have thousands to tweets sent out to them per day.

Any suggestions would be welcome but at the current moment, I am out of ideas.