Looks to me like price leads the google trends?
My analysis is that there is a cycle in price in crease like this.
Traders buy and price rises -> "Get rich quick" idiots search Google for "Bitcoin" -> 3 buisiness days later when their SEPA deposit clears there is a spike in price.
Don't look at it as the searc volume raising the price, look at the search volume raising the price on a 3-buisiness-day delay. So that spike on 2013-04-02 was actually the smaller one 3 days later. I'll do a more in depth analysis later.