There is no rule for this and it will depend on a lot of things such as your experience, the complexity of the system, the non-conformance situation, availability of personnel and auditors and the maturity of the system.
Some organisations will have the stage 1 and stage 2 within a week of each other, this happens when the system is really simple, the client has experience of running and implementing management systems or we know the consultant who has helped with the implementation as this gives us confidence that you will be ready.
Generally, most people will leave a month gap which is enough time for them to fix any errors to enable the stage 2 to run smoothly.