How do I efficiently find the number of tweets & retweets in a time span using R? (TwitteR package)

I want to find out the number of tweets, favourites and retweets (cummulative is enough) of the UK General Election candidates of several parties (>2000 candidates) in the 2 months before the election. So far I have tried to make a loop using TwitteR's usertimeline, and then (in the loop, because I don't know how to save it otherwise) saving the number of tweets and retweets and favourites. I want to find out the number of tweets, favour