Are there any breed specific rescues in your area? You could take her in and then work with a rescue to find her the perfect home. If finances are a concern, I would not take on so many dogs. While you would be helping another, it could potentially hurt one of your current dogs if something were to come up that they needed financing for.
From experience with english bulldog, mine has had 4+ surgeries for cherry eye (keeps coming back even though his opthomologist is one of the best), he has had brachycephalic surgery (for his breathing issues), tail amputation (for ingrown curly Q tail) and he CANNOT be walked much or outdoors much even after successful surgery, he gets very tired and takes him a while to recover and catch his breath. He loves to swim, but cant really swim often because bullies are prone to aspiration pneumonia. As far as personality, Clyde (and most other english bulldogs I have met or talked to their owners) is extremely lazy but gets short bursts of crazy-strong energy where he charges around the house like a linepacker/bowling ball then sleeps endlessly like a rock. He has a dominant personality (hence the term "bully") and will not take any other dog or male human "challenging" him- he isnt aggressive but needs a firm leader to be stern with him (of course I dont get physical, but my voice alone will stop him in his tracks).
Having to do over, I would not adopt another English bulldog, not for the financial reasons, but because my family and my love for dobermans include a very active lifestyle. I absolutely LOVE my smushy face bully, but it is not fair to take the other 2 dogs everywhere (hiking, boating, beach, walks, play dates, dogpark, etc) and have to leave him behind.
(i didnt mention that MOST EVERY english bully has allergies, somethign that can be extremely frustrating and a bit costly to maintain. I am one of the lucky ones, Clyde has only mild allergies and minimal facial staining but I have yet to meet another without blasted allergies)
Unfortunately there are no breed specific rescues hereabouts and I would hazard to say there aren't any in the whole of Spain.
Conna, (which is her name) has weepy eyes which go gooey and to be honest I think she suffers with them.
Her breathing is really bad. And whilst I want to help her with it I do not think for one second that I could afford the surgery to try and help her even if my Vet could do it. We do not have specialists per say, we do have the Veterinary Colleges but they charge you for the privalege of basically of using your dog as a test case and even then, I am unsure if they do this operation or not.
She does have outbursts of energy but as you said, sleeps a long time.
She is kind of stubborn, but then she hasnt had any proper handling or training.
I am not sure if she has any allergies, but from what you say I wouldn't be surprised if she did.
I just feel so bad. I kind of promised her (I know she is a dog and doesnt understand) that I would do my best to help her and now I am not going to be able to keep that promise. Which kind of hurts.