Pet policies

I live in Alabama. In oct of 09, my significant other and I bought a trailer. It is paid for and is in both of our names. The landlord has a no pet policy. We didn’t know that when we purchased the trailer. They agreed to let us keep our 3 dogs if we fenced in the back yard, but only because we owned our trailer. In March of 2010, I left my fiance and took 1 dog with me. The rental agreement got rewritten into just his name. But both of our names remain on the deed to the trailer, that never changed. Maybe 4 months later he called and asked if I would like the other 2 dogs back, and I took them. Well, he is moving to florida and decided to give me the trailer back. The dogs and I had been back living here for a few weeks when I get a letter on my door telling me this is a pet free park, consider this my notice to move. I am 7 and a half months pregnant and going to be a single mom, I can’t really afford to move else where right now. Can my landlord legally go back on the original agreement and tell me that I cannot have my 2 inside dogs? They only go out to potty in the fenced in back yard we put in. She said when I left and took the dogs that voided any previous agreement.