takayama snow wall, April 2015

I have plan to Tokyo on April 8, 2015 and end of the trip, fly from Osaka to my country on April 17, 2015. Is that possible to visit Snow wall Takayama? How long i need to stay/where to stay? I also interest in visit Shirakawa Go. Please advise . thanks

I assume you mean the snow wall along the Tateyama-Kurobe Alpen Route, rather than "Takayama". I am not aware of a snow wall near Takayama.

The opening dates for the Alpen Route for 2015 have not been published yet. In recent years, it has always opened on April 16 or 17. So, it looks like you may not be able to see it. If it were to open on the 16th, you could theoretically see it on the 16th before leaving Japan from Osaka on the 17th.

How long i need to stay/where to stay?

The Alpen Route can theoretically be visited in a day trip from Osaka. No need to stay overnight. But an early-morning start from Toyama will make the day less hectic.