Queens Gambit accepted

Hello fellow chessplayers,

I play the queens gambit a lot, and it mostly turns out to work well :D. But sometimes opponents come with a non-theoretical, but very annoying reply. Game's can go like this: 

Experience teaches that this a5-b4- pawn chain can be very annoying. It blocks Nc3(seen as the best developing move for this knight). And after Nd2 your c1- bishop is totally blocked from action. Is there a good way to handle these problems?

play for e4 and make use of the weak c4 square and the weakened diagonal a2-g8. Cheers

melvin is completly right, in this position you can win immediatly. I talked about it from a general point of view.

Although I'm not a fan of 3.e3 in the QGA, if your opponent plays wrecklessly like this(no one who seriously plays the QGA would ever play 3...b5 anyways), then you can usually punish them on the h1-a8 diagonal.  

The correct move is 3. Nf3 otherwise black can play 3. ... e5. Besides being theoretically sound 3. Nf3 often provokes black to try to defend his pawn which is not a good idea in the queen's gambit accepted.