Nothing is simple. The form 61-4P lists approved foreign States allowed to conduct the flight test. The only Asian country there is Hong Kong, but then it bangs on about others maybe holding a Legislative Instrument. Ask the question of the simulator centre that you propose to use and require a copy of their CASA approval before parting with any money.
If you absolutely must do it in a B737, I would suggest you identify where and when you can do the flight test, then find a tame FE here who can log into the CASA Flight Test Management System and nominate a place, date and time for the test. The catch for an independent FE would be nominating an AOC number, so that person will need to be affiliated with a Part 141 or 142 training organisation.
I looked at renewing an IPC for a colleague independently in a light twin, and although my privileges technically allow this, it was impossible to simply jump in his aircraft and just do it without an AOC to quote.
Re the other query about what time limit is imposed before recurrent training is called for, under current CASA rules there is no limit. An IPC on type revalidates all. It is up to the Examiner to determine whether the standard has been met. Depending on your experience and skill level, 18 months out of the saddle should not require much more than a dry run the day preceding the test.