Wordpress XML file import script / plugin

I need to create a script or plugin that will be able to import data into my wordpress installation. I receive on daily basis 50-70 articles in xml format (which has a structure like title, date, category, subcategory, article, summary. These are individual xml files - one for each artilce. Now, I need to create a script / plugin that will import this data into my wordpress installation as a proper post with categories, date etc. I need this urgently. I have uploaded a sample xml file that needs to be imported into wordpress so that you can have an idea about how much work is involved. Thanks