Changing cell references in formulae?

Right...

I have a macro that inserts formuale into cells on a summary sheet, these formulae refer to specific cells in the backup sheet, the trouble is sometimes this information is in the first column, sometimes in the third column of the backupsheet. If I was referring to the cells using Cells(y,x) I could easily add in an adjustment, i.e. Cells(y,x + adjustment) where adjustment is either 0 or 2. However as these are formulae the only way I know how is to do this...

Cells (1,1) = "='Backup Sheet'!A1"

I have A LOT of these formulae so don't want to go down the path of having an IF statement at the begining then two separate list of code... can anyone help? Would greatly appreciate it! Thanks in advance! Chris.