external display

I connect my macbook 2011, 11" intel HD Graphics 4000 1536 MB, El Capitan, to a P2319H Dell Display, which is 23", 60 Herz Full HD (1920X1080). I am using a vga cable, original apple. In the preferences, as recomended, resolution is set "Default for display" - 1920X1080). It works, but I have a poor resolution to texts, which is my main job. Dell does not provide a driver to mac users. Any solution?