Hi Sandra,
Awesome news that you’re heading back to Grecia. That’s where I first lived in Costa Rica. Great town – loved the farmers’ market.
If you’re going to be there for a month, I would recommend a vacation rental. That’ll give you the opportunity to really live in the community.
Craigslist Costa Rica is where I found my rental. Of course, just as with CL in the States thoroughly check out the listing and the owner before giving a deposit.
VRBO.com has good listing too, as does http://www.american-european.net in their vacation rental section.