hello
Don't worry too much, it can sometimes take hammies a while to get used to their new environment, especially if it is bigger. My rescue hammy has a 4 level imac hamster cage and it's huge, she never goes on the 4th level whatever I do!!, but she is happy so I don't try and force her.
You did all the right things by putting some of her old bedding in there, and its great she has a bigger cage.
Just continue to do what you are doing, giving her treats, talking to her and stroking her. Make sure the cage is in a quiet place, anyway from too much noise, this will help her too. Also try hiding some of her favorite treat around the cage, that may help her to venture out!
Hope that helps