Opening, black and white

I am arigendler and I like to play chess.

My favorite opening in black is the Sicilian Defence, Najdorf Variation. But I have a problem, sometimes I can't play this because my opponet doesn't know the Sicilian Defence. For example, look at the next diagram.

I have the same problem with the Queen Gambit, I think it's a good opening, but I can't learn all the variations alone. I hope you will help me with my problem.

Thanks,

Ari