summing based on a criteria but the criteria is not the format i want

Hi there

hopefully the question is in the title: summing based on a criteria but the criteria is not the format i want
I have come up with a solution in Sheet1A but i don't want to add another column.
Please ask any question if the question is not clear.

See the attached.

1. How do I get the sum of ValueA for the month of June and put it in column G2
2. Assume that hourly data will be appended to this so in future I will want to get July values…etc
3. I am looking to do the same for ValueB & ValueC
4. I could add another column in column as I have done here and this works (Answer I want is in column J) see Sheet1A

Row Labels	ValueA	ValueB	ValueC			Month I want
8/06/2013 2:00	2	89	21			0
8/06/2013 3:00	30	81	66			
8/06/2013 4:00	65	89	58			
8/06/2013 5:00	24	85	57			
8/06/2013 6:00	100	86	60

Tks