Summarize:

After a couple of days you can begin to allow your cat to explore some more of the house. After making sure that all potential routes outside are closed and secured, invite her to have a look around a few more rooms. Gradually allowing access to other spaces will help to lower her anxiety. Keep an eye on her when you allow her to explore more and be on-hand to comfort or play with her if she appears stressed. If you have a cat-leash you could use it to make sure she is unable to make a run for it. If your cat is not used to a leash this could just make her even more stressed out. You can use a plug-in pheromone diffuser to release scents that are designed to calm stressed cats. You can buy these from your local pet store or vet, and they help to create a more reassuring environment after a move. It is a particularly good idea to use one in the room your cat will be spending a lot of time in at the start. Different cats will react in different ways to these diffusers and some may not react at all. You could keep some catnip handy as an alternative. It's important to be relaxed around her, and to allow her plenty of time to adjust to her new surroundings. She might take a while to get back to her old personality, becoming more withdrawn or quiet after the move. Showing patience and sensitivity will help to reduce any anxieties and create a comfortable and welcoming environment. While you gradually introduce her to her new house, it's important that you don't allow her to get outside yet. Keep her in the house for two weeks so she can become fully acclimated to her new surroundings before you let her out. Spending this long in the new house helps to establish it as her new base, and lower the chances of her trying to make her way back to the old house. Take extra care to make sure your don't leave doors or windows open in this period and generally be observant and careful. If you have a very adventurous cat who is desperate to go outdoors, don't give in. Keep her in for a minimum of two weeks; the amount of time depends on the disposition of the individual cat.
Open up more rooms. Consider using a pheromone diffuser. Be patient. Keep her indoors for two weeks.