If you have the money to spend, send the horse to the trainer to see if more training will help the horse work for you. It can never hurt. This will, if nothing else, help the horse find a better home than if the horse had less training. Money spent on good training is never a bad thing.
If training works REALLY well then you have the horse you like and she works for you. If the training only works some what well, the horse has gained some know how that will serve her well in the future with a more experienced rider.
If you do not have the money then send the horse back and carefully (very carefully) shop for a horse that is appropriate for what you need.