I agree with Tdol. If you already have a CELTA under your belt you certainly don’t need another Certificate. In most places the basic requirements for entry level teaching positions are a degree plus a TESL/TEFL certificate - not necessarily a CELTA, though CELTA is a good Cert to have.
Of course, the more you have to offer in terms of qualifications and experience, the better your chances of landing a well paid job with opportunities for advancement. However uunless your intention is to remain within the
ESL industry and build a career for yourself in this field then your BA and CELTA should be sufficient to secure a decent job abroad.
If, on the contrary, you want to further your studies then you could consider moving into CALL (Computer Assisted Language Learning) or look at MA programs in TESOL.