Insert Column when a sequential isn't found

Hello,

I have a problem, where i have a row of numbers and data underneath that are imported in they sit in row A and run to column 20, these numbers are sequential 1,2,3,4 etc, but there are sometimes that certain numbers are missing, what i need to do is to insert the missing number and column when they are missing.The missing numbers/column may be random but it always will finish up in the correct order when imported.

Hopefully it should be to much of a problem, i've attached a sample file to explain the problem better.

thanks reg