Under a time constraint, working with OpenGL doesn't really make a lot of sense. For a 2D game, you are probably best served using a library such as SDL, SFML or Allegro, all of which use OpenGL behind the scenes. By working with such a library, not only are the OpenGL specifics handled, but so are the file loaders, music libraries, tertiary math libraries, etc... Keep in mind each of these libraries represents MAN YEARS of work, most of which you will have to replicate and debug yourself if you "roll your own".
If you decided to go the SFML route, with your baseline knowledge of C, this tutorial will get you up to speed fast with both C++ programming and using SFML. If you go the SDL route, which is a bit more C'ish in style, there are a literal ton of tutorials on their site. Allegro is in a bit of a transitional state at the moment, but has a fair wealth of tutorials available as well.