Iteration is a key concept of making quality software. No project is excluded, no matter how large or small. It may be worth taking a step back, losing your obsession about making it 'done', and build the system such that changing and extending it is trivial. If your data is database backed, this should be a simple matter of adding rows. If that is a pain in the ass (because you actually have to use a db client and make SQL statements), then consider adding a front-end for updating the data.
That's my 0.02