I have about 300 domain names all .com .net .org domain names at the moment we register them though onlinenic.com but I need a script / program that will allow me to automate the renewal process does anyone know of such a script (asides from the one that onlinenic has).

OnlineNIC provide registration API. You can make renewal process using PHP based on that API. Login to your control and look at API reference.
See also Template v.3 for example of code.

I am not aware of any companies that have interfaces written for onlinenic.