i need to convert 80,000 postal codes to a 9 digit numeric value.

where M5R3T8 converts to 135183208
and M4P3J9 converts to 134163109

each letter of the alphabet needs to reflect the numbers 1 - 26.
a = 01
b = 02
c= 03
d= 04
e = 05
f = 06
g = 07
h = 08
i = 09
j = 10 etc

I am currently copying the postal codes to a separate sheet and doing a find and replace. sounds crude, i know but it is the only way i know. Hope you can help!

thanks!