I'd do it the other way around. Do your DELTA first. It's short, sharp and painfull. It'll help you refine and develop your teaching skills. It's like the CELTA but enormously harder.
The MA is great for theory and understand the language, but won't help your teaching at all unless you have DELTA level teaching skills and know how to integrate the ideas into lessons. It also takes for longer to do so that next step in your career is a long way off. Having said that, 2 years experience isn't a lot to take to a DELTA. I think it's the absolute minimum in fact.
As to the post about changing careers, do a CELTA. It's the most recognised course worldwide - it'll get you the job.