How about we rather hope that the price is going to stabilize a bit above $300 before the end of the year. Bitcoin is not ready for a price of that magnitude.
The network would not be able to support the influx of users and the number of unconfirmed transactions would skyrocket quickly.
1.If greece was not in the eurozone and still was using drachma as their currency - crisis would be more beneficent to bitcoin.
2. Expecting that suddenly every greek would use or know about bitcoin just because theirs economy is crumbling is stupid.
3. Even if they turn to bitcoin, price of btc would not be pumped to the moon at all.
For now Bitcoin reaching $500 is a fantasy scenario and won't happen before 2016 for sure, and even then it will be hard to achieve.