I think the right time to buy is after entering the month of August, there we can see where the price will move whether to reverse and rise, or continue to continue the downtrend, if the price has directed back and up movement then you can buy, instead, think back to your plan to buy
But may be by that time we may see rise in the price and if it does then it would be too late to buy bitcoins as current price is really good to grab some coins at cheaper price as once it start rising it would be really hard to stop it and if we wait till August and if price goes by that time then we would regret for not buying at present so its good to buy some at a moment and keep some money in hands and if price falls even lower then we can buy more at that time.