rotating a texture

Is it possible to rotate this texture (in opengl)… http://img441.imageshack.us/i/tileset512.jpg/

to place TR at the top left, TL at the bottom left, BR at the top right and BL at the bottom left or counter clockwise lol

what i am trying to do is in the screenshot below

http://img196.imageshack.us/i/2x2tilemap.png/

The idea is to rotate the texture so i can get the correct coordinates and frames from it onto my quad on the 2x2 tilemap. So TL should be the first frame mapped onto the quad.

Oh also the coordinates 0,0 starts at the top left!

But i think the textures may still appear weird so generally what would be the best way to make a spritesheet,i.e be able to get rectangle from a texture and move along whatever axis as i dont feel to far away.

Or even somehow CHANGE the texture coordinate system to get 0,0 at the top left??

Thank You