Sorry this is much later, but you should find an emergency vet in the area. If the dog has lasix (furosemide), I would give another dose of it if he is in crisis, but other than that, not much else you can do at home. You can also try and tilt the dog with the head down to attempt to drain some of the fluid in the airways out of the mouth...it's worth a shot..I've seen it done in an ER.
Hi. Like Shannon, this is much too late to be useful to you - and I am assuming you managed to find an emergency vet (hope so). There is virtually nothing that can be done in the domestic home situation, because dogs in severe difficulty with heart and respiratory symptoms need close professional care - and usually a supply of oxygen to help them breathe. Dogs in respiratory difficulties will invariably sit or stand, because this helps them to breathe a little better - and some dogs will be so afraid of lying down, they will actually fall asleep in a standing position. It is helpful to support a dog as much as possible, perhaps with pillows either side to keep them upright. The problem is, these conditions totally exhaust them and they are in real danger of collapse, whereupon they find breathing even more difficult, hence trying to keep them in an upright position (without distressing them further) can help a little, but only while an emergency vet is found. Tony