Adding data from one column using another

Hello,

I am having a real problem with an Excel formula.

I have a worksheet with variable rows and a number of columns. I need to add together the values of particular cells in one column, but only if corresponding cells in another column fit within a date range. I need to do this for all rows (although I won't know how many rows there are until I have imported the data), and for different date ranges. I need to add the values together on a seperate sheet.

The reason for this is that I want to sort activity put through a particular account into weeks. The data is input with a date, but i need all data up to and including the week end to add together to give me the week's total. I need to do this for each week of the year.

I have tried =IF(AND(criteria<range,range<=criteria),cell,), but realised that I would have to re-type this for each row. There could be as many as 400 rows, and never less than 110.

Any help would be appreciated.

Thank you

Dominic