QGIS 2.6 How to create a vector (shp) layer from an excel file?

I am using QGIS 2.6.1 and have worked in an Excel file database (which was actually converted from a Shape-File). I have managed to convert it as CSV file and load it into the GIS (displays data fine) but I have trouble to convert it to a shp-file. I can view it but I can´t add or alter data in this file. I think I have to save it as a database. Any clues how to convert the xlsl-data to a database and finally to a shp file?

Thanks in advance