Ridiculously long calculation time

[dbconfession]

Hello everyone. This is my first post.

I have an iPhone app for managing my budget and tracking my expenses. The app has an export to excel feature. I use this export as a data dump to build my spreadsheet which uses arrays to ertieve the innformation required from the data dump tab.

Essentially it is a list of expense items down the left side, with 12 months across the top. Here is an example of one cell's formula

{=SUM(IF((TEXT(ixpenseit!$B$2:$B$65536,"mmmyy")=C$3)*(ixpenseit!$D$2:$D$65536=$B5),ixpenseit!$I$2:$I$65536))}

I have no problems with anything in the formula; it works great. But since the formula is so complicated, the calculation time is enormous and makes the spreadsheet worthless.

For now I have disabled auto-calculation but would like to know:
1) Is there a way to only calculate selected cells instead of F9 calculating everything?
2) Anyone wanna take a stab at simplifying my formula? Maybe there's an easier way to do what im attempting. Keep in mind I can't alter the column/row structure of the data dump.

Thanks in advance guys.

[shg]

Limit the row reference to the range you need. Read about dynamic ranges: http://www.contextures.com/xlNames01.html