Excel 2007 : Help on value retrieval, retrieving only current value.

Hello guys. I've been making an excel sheet for my rental management business. And I have considerably done almost every thing except the part when a tenant is about to go. The scenario is, all the expenses (rent, electricity, water bills) left from his stay are calculated and then individually paid off by his deposit. The thing is I need to know how to get the totals of the expenses from my other excel sheet without the values ever changing once it was been acquired.
for example:
I have a table on sheet 1 (all of which are also connected to another excel sheet, in the form of a FORMULA, therefore they are always changing.)
A B C D E
1 Name Occupying Rent Electricity Water
2 Mr. Someone Room1 100 50 10
3 Mr. Sometwo Room2 50 30 5

Sheet 2. I need a way to get the current values so that the computation will tali, and not change whenever there is a new tenant on the property.

Thanks in advance.

Bump......