Web Query's

Hi there,
I have set up a similar spreadsheet set up as follows

EUR GBP USD TOTAL in GBP
jan 12 11 15 ?
feb 13 14 16 ?
mar 11 10 12 ?

In the 'Total in GBP' i am basically trying to achieve the obvious. I have set up my web querys on a different tab (one for euro conversion and one for US conversion) and i simply reference to them for the 'Total in GBP' formula, however my problem lies with updating the spreadsheet as the exchange rates will obviously change but i don't want the existing figures to change. When it comes to the end of feb i want to apply an exchange rate taken from 1st March on all the feb figures. Is there a way i can do this without having to change all the formulas and references at the start of every month? So basically once the the feb 'Total in GBP' has been calculated it won't change when i come to do the march calculation. Is this at all possible making the spreadsheet easier to manage?

Thanks in advance, i'm sure with the wealth of knowledge available on this forum someone will have an idea!

WTB

WTB, If you submit an excerpt of your worksheet it would help.
You may have to create two data fields, one that changes and one that does not.

Ah ok, forgive me i'm very naive when it comes to this sort of stuff. I've attached a simple version. Ideally i want to create a monthly summary for each with a currency rate applied to all the figures taken from the 1st of the following month. I would like to be able to type the raw data into the income tab and the monthly summary to work its self out. Through my limited excel knowledge i can do this however i get stuck when it comes to updating the web query's and them changing historic figures. My example shows January has been calculated, but how to i fix those figures when i come to work out feb, march ect. Do i need a separate tab for each months summary? And also is there a site that will allow me to set up currency conversion web query's in advance. I.e have the web query set up for March 2010 EURO/£ conversion even though this figure does not yet exist? (I think that last question may just be wishful thinking!)

Thanks in advance

WTB

No one got any ideas? I'd really appreciate the help!