You will maybe receive a lot of pms from users willing to offer the services you look for. Some will even try to convince you about his professionalism in community management.
My advice to you:
- Try to not hear from anyone who hasn't a verified portofolio.
- In addition to community management, You will need a graphic designer to create you announcement threads and maybe an advertisinh signature, so better to hire someone who can do both tasks.
- As you are willing to pay in btc, In "Services" sub-board of this section, you can find many trusted profiles from whom you can choose the suitable one for your needs. I suggest user "Zwei" or "hugeblack" who are professional designers + community managers.
- Paiements per month may not be so attractive unless you escrow the funds before to start.

I wish you the best of luck .