Seems like a "no brainer" to me. You want a job right now right?
Can your immediate employer use your current and available instructor rating NOW, or should they wait however long to take advantage of your ATPL (but only when you have enough hours to qualify for it?). Mate do your Rating first and study ATPL while you are working.
As was said previously, don't bother doing the instructor rating unless you seriously believe you can teach people. There are enough looser waste of time instructors out there that are good pilots but not cut out for instructing. Please don't add yourself to the list.