Data Transfer B/W Excel with Calculations

Hi,

I have two excel sheets, A.xls and B.xls

I have lots of data in A.xls and need to consolidate them in B.xls.

What i want:
1. Get the file name from a column given in B.xls (cause the 1st excel name
can be anything)
2. Once this is done, next i need to get a count from a range depending on
the condition, say like i have columns M:U filled with data (value < 100) and
i need to get the count if data is between 60 and 100. Just count.

How do i do this? And more complex calculations will follow depending on the
success of this.

What i like to do is to select the filename and then proceed.

Can someone help. Thanks..