Not sure if this is the right spot but how do you get level two warehouse? My critters explore like crazy and I don't have enough room for everything so I need to upgrade. 

You need the blueprint :)

Most likely to be found cheap in the Item Trades, although it is a high-demand item. I wouldn't recommend the State Store, those prices are exhorbitant.

You could even try the giveaway section in the newbie forum. Lots of us give stuff away free to newbies, although off the top of my head I don't think I have a warehouse 2 lying around currently...