Spanish study

How many hours a day should one study a language in order to grasp it within a year?  

I've read somewhere that for an English speaker, you can get to about B2 level with around 1000-1200 hours study. That's obviously highly dependent on a lot of factors (what level you're starting with, whether or not you have experience with learning a language, etc.) but that's quite a lot for a year.

There is an article over at the Rocket Language Blog that discusses the time required to achieve fluency.  In addition to formal "study" I also think it is important to do other language learning practices each day, such as watching videos or listening to talk radio in your target language, speaking it whenever you encounter a person who speaks your target language, and thinking about things in your target language, talking out loud about what you are doing, seeing, hearing, etc.