how to have 2 mathemical functions based on text value of a cell

Hi,

I'm putting together a table which shows monthly costs versus Total costs.

Is there a way I could use if two choose between two option dependent on the value of cell A1.

Example

A1 = "Totals", multiply Subtotal in A13 by 12.

A1 = anyother value multiply by 1.

Something like:-
=if(a1="totals",(a13*12), =if(a1<>""sum(a13*1)

Any help much appreciated