Hi Marta
I'm really sorry to hear that Gapa is missing and I hope that by the time you see this she will have been found safe and sound.
Unfortunately, most search and rescue dogs (and certainly all the operational dogs in the UK lowland teams) are trained to find humans, not other dogs and therefore they would not be able to help you find Gapa. I know it may seem that they should be able to search for any animal, but they are specifically trained to search for human scent and to ignore other animal and dog scent.
I see that you have her registered on DogLost so hopefully you will get lots of help from them, I know from experience that they can help rally people in the local area to help search so I hope that you find you get lots of volunteers.
I'm sure everyone on this forum feels for you, as we are all dog lovers, and we all hope that Gapa is back home with you very soon.
I'm so sorry we can't help.
Best of luck
Judith