add a line to end of the file using VBscript

HI

I am working with a software that only accept Vb script commands.

I have a file that has 8 columns. I need to add a line at the end of the file using VB script

I need this line to add numbers of amount column and put 22 in 7th column and leave the rest empty.

example:

added line

                                                                      66.07+9.88=75.95                                                22

the files have different number of rows. please help