What should I do? pet ok on lease but landlord won't let us have our dog

Basically, we've been living in this house since January 2015. We had a year lease so now our lease is up and we've agreed to do month to month. Our lease says pets are allowed if we paid a $100 pet deposit (which we did). We've had our pup for months now and our landlord stopped by one day and saw her and then a couple days later we got a letter in the mail saying they talked to their lawyer who told them they should evict us immediately but "they aren't going to do that". They want us to get rid of our dog. The sick part is they have 9 freaking dogs themselves. We've gone months with our pup, she loves us, knows us and misses us when we're gone. Finding a pet friendly place where we live is damn near impossible. I've been crying all day because I don't want to put her in a shelter and I really feel like no one will/can love her the way we do.