For a specific date, if you want to process only one month, you need to specify the month (and usually the year so you don't get say April 2004 with April 2005). How you do that depends on what you want. The easiest is to create a query. Create two alias columns, one for year and one for month using your date field in the table I will call MyDate. It would be like this:
CheckYear: YEAR([MyDate])
CheckMoth: MONTH({MyDate])
Then in the criteria section of the query for CheckYear put this: [Enter Year wanted]
Then in the criteria section of the query for CheckMonth put this: [Enter Month wanted]
Once that is complete run it and test it.
Once it works, you can create a report using the report wizard from that query.