600 USD wow, I really hope so, that'd go a long, long way to repairing BTC's image/reputation. Correct me if I'm wrong but if the Grexit happens then other countries will be in financial trouble & it's not impossible that the Grexit could cause a snowball effect?
I'm sure I read somewhere that Greece owe France an astronomical amount of fiat.
The chances of bitcoin boosting to 600$ till September is HIGHLY UNLIKELY, I think it will rise to 300$ itself till December. The price stabilizes and it needs more demand and supply in the market to boost price and that can only happen if bitcoin becomes a trend through media and gets attention, or a lot of people adopt to bitcoin and we supporters start talking more about it.