Return a count of twitter tweets for keyword within timeframe

Question

Hi there...
I want to make a small web app to query twitter for a keyword within a specified time range set by date and time... I then want the app to be able to automatically count the number of keyword related tweets within the timeframe and provide me with a tally...
e.g.
I want to query twitter for the word "football" on September 3rd between 07:00 and 12:00 hours. The app then returns all the relevant tweets... When this process is complete it, the app would say "41 tweets were found" for example.
I can do the first bit in terms of finding the tweets in the given time range using the twitter API - how would you recommend i coded the count function...?
 
Thanks in advance.