Module customisation OpenCart - Import/Export

We have three OpenCart websites selling shoes and clothes online. We have several features we would like to add over time, but the initial one is to do with the popular Import/Export module that imports a product file to populate the site. Some additional modules we have allow additional information to be stored through the admin on each product (such as a roleover image), but this is not carried through to the Export tool which leaves it off. This therefore means we lose the data when re-uploading the stock file. We need someone with php experience to add the necessary lines to the export.php file to include these additional bits of info for all three websites. Each website is slightly different.