Instead of looking for a resort with reliable wifi, you might be better off investing in a 3G USB Modem like this one:
http://www.amazon.com/Huawei-E173-Unlock...B0055310KQ
Once you are in Costa Rica just get a prepaid 3G SIM and pop it in. It should give you high speed internet access where ever you are, whether you are close to wifi or not. This is what I did when I was in India recently and it worked out very well. I am not sure if Costa Rica has the same kind of mobile data coverage, but it might be worth investigating.
http://www.amazon.com/Huawei-E173-Unlock...B0055310KQ
Once you are in Costa Rica just get a prepaid 3G SIM and pop it in. It should give you high speed internet access where ever you are, whether you are close to wifi or not. This is what I did when I was in India recently and it worked out very well. I am not sure if Costa Rica has the same kind of mobile data coverage, but it might be worth investigating.