The first thing to learn about bitcoin is that nobody knows something that you don't. You may get 100 answers to your questions about future price, but these are simply guesses you could have made. Only you can decide what a good price for you is.
I agree with RodeoX, nobody really knows. I would suggest you to buy a bit less before Aug 1, and buy some more after that, if the price goes down. But it's your decision, though.