batch processor, and customized image maker

I need a batch processor created that can produce images for me automatically. There will be a base image with only one line of text varying. I currently change this one line of text by hand in Photoshop over and over again. It gets to be time consuming. I am looking for a way to automate the process. I also am looking for this tool to be able to work online. A person would type in a line of text, and the proper image would be generated. I have attached a 2 page .doc file that describes things in more detail. It shouldn't take more than a few minutes to look over. It should be very straight forward. It also contains some sample images in .psd format.