Did she know that where her wings are?
Definitely not, when her wings got removed, she doesn't became aware of it because of liquid she drunk. She got to know it at next morning. After that event so much time has been passed and never mentioned that she know where her wings are. She doesn't have far-sight or witch ball to know where is her wings are, they are still unaffected or not.
Why don't she grow her wings?
Because she can't, she made Diaval as a shape-shifter and called him her wings. She needs her wing but she can't grow them back that's why she made Diaval as a raven shape-shifter.
Why She didn't tried to get back her wings?
As per her actions, its clear that she only wants revenge. She doesn't given a though of getting back her wing and she might not even know if they are still there or not. And direct fight with Stefan is risky because he knows her weakness.
But she can do that....she can do that but why not bring back wings?