The OP does not say, but does imply, that s/he had written the original code being modified.

If that were the case, the OP would have the background to make the desired changes and wouldn't have needed to ask.

Had the OP simply stated "this is legacy code, and I don't want to pay to have it modified", the responses might have been different. Might. (Though to be honest, I'd still second the 'Hire a programmer!' sentiment...)