The only way to answer this for your situation is to cost up the renovation you have in mind, check you can afford to do it, then compare that with houses in your area that already have what you want. If there are other areas you’d be happy to live in you could include those as well. The best way to cost up a renovation is to work out exactly what you’d like to do or talk to a designer about what you’re trying to achieve, and then pay an experienced builder or quantity surveyor to estimate the total cost, including things like council consents. You should also include a healthy allowance for cost over-runs and unforeseeable challenges, such as rotten framing.