joomla component edit

Hi, We have this component installed for joomla - [login to view URL],com_mtree/task,viewlink/link_id,99/Itemid,35/ ( [login to view URL],com_remository/Itemid,51/func,fileinfo/id,73/ ) We need it to be edited/rewritten so the main and required field will not be the city, but country. I.e. city should be there as the required value, but not the one, which is required to create venues. Venues should be created by country. Also, there should be an optional field for State. Some other minor field changes possible, but the above is required. Need this to be dona ASAP.