Have you tried Zyrtec? It's the strongest over the counter med for both indoor and outdoor allergies. It comes in a generic now so it's very inexpensive, especially at a place like Costco. If medication doesn't work, generally shots are going to be your best option (you would want to check your insurance coverage, tho).

Have you seen an allergist and been allergy tested? That will be the first step before your shots. I have been getting shots for about 6 mths now. (I am extremely allergic to dust mites.) It will take about a year before they begin to work, and it truly is about a 5-year commitment. The first 3-4 mths required that I get the shots twice a week (from then on it is once a week). They generally don't hurt much at all (very tiny needle).

ETA: Most dogs are very happy in their own dog beds, still in the same room at night as their owner(s)...this is going to take some training, however. I don't have any wise words on getting your girlfriend to see this point-of-view (maybe someone else can help you there). She might just really love her dog sleeping in bed with her. I have found in past relationships that a dog plus two people doesn't fit very well on the bed!