Example of functionality: http://propiedades.com/buscar/Distrito+Federal/%C3%81lvaro+Obreg%C3%B3n/Guadalupe+Inn/Venta/Residencial/Departamento
The plugin / module must be developed for Joomla 2.5.X or Joomla 3.0.X.
The plugin / module must have a search of elements, the results are shown on a map and every result is going to have a exact location on a map. All data is pulled from Joomla K2 extra fields.
The plugin / module must have a filter, for example, price range. When you adjust the filter the map will refresh and show the filter result.
When you click on a result, the module will show you a window with the main picture, read more link and its price. If you clic on the read more will take you to the k2 element.