@GinnyP
As you have probably read; Getting your Residency can happen from 'up there' or if you're already here. Just a have a good Residency Service helping you. There are things that you have to do 'up there' ... like getting your FBI background check (which requires a set a fingerprints), copies (get extras!) of your birth certificates, getting a CR consulate to apostille your documents (note: there are different things that you will need, depending on which type of Residency you apply for.. like a bank letter for Rentista; a certified and signed letter from SS verifying your benefits; etc.) Everything from up there needs to be translated into Spanish... so your Residency Service should help you with all of that and make sure you have all your ducks in a row before they turn in your application.
I sort of did it from both ends.. I made contact with a service before I left the states and was able to procure many things while I was there... all sent to my service (they had a guy in Calif.)... Then I came here. The person from my service that was here compiled all of my data (her liaison in the states sent it all to her after apostille and translations) and she then met me at a police station in central SJ to get a copy of fingerprints and some passport photos that were required as part of the application package; and to a lawyer's office for a letter of verification. I only had to go to SJ for 1/2 day... she put the application package together and walked it to the Migracion office herself From then... it was 4 months before I was notified that my application had been accepted for Processing Only. So at that time, they sent me a document called Expediente which I made copies of and kept with my passport. That document meant that I was free to stay in CR without leaving when my passport stamp/visa expired. Before that, I was still obligated to leave and return as per the dates on that entry stamp.
I then waited another 11 months? to hear from migration that my application was Approved !! (they sent me a new document called Resolution) My service then sent me to the administrative office for the National Healthcare system (Caja) to join that... it is mandatory to join if you want to have any sort of residency. I went to the office in San Ramon (no line) and took a lawyer with me who helped me to opt-out of having to pay into the CR Pension program (because I would eventually get SS)... you cannot opt-out of that currently... the fee is around $100 a month and is added to your monthly Caja costs.
Once I had joined the Caja (they give you a receipt on the spot) I went to BCR (banco de costa rica) to apply for my Costa Rican ID card (cedula)... I had made an appointment at the BCR (Banco de Costa Rica) closest to me that offers that service; for the day after I went to join the Caja. It was easy, you pay, they look at your documents to make sure all boxes are checked; take a photo, and then a few weeks later, I picked up my ID at the local Correos de Costa Rica (you can do the ID thing there as well... but you'll still have to go to BCR to pay the fee).
So... I'm glad I did what I did up in the states before I left; and I"m glad I was here for the final steps before the application was turned in. It requires patience, many questions, and more patience.
I'm sure it's harder to get Residency in the US than it is here.
Good Luck