A realtor is a service provider. They are providing a service to you in helping you find the dream house/property you are looking for. And for this service, you pay them. If they are giving you poor customer service, it's high time to find someone who will go above and beyond. And in this market, it shouldn't be too hard to find.
With that said, it doesn't sound like she's able to provide you with what you need right now and you should NOT feel obligated to her for any reason. It doesn't matter if she's the one selling your current house. Find a realtor who deals in farm properties and I bet you'll do much better without the frustrations you feel now. And good luck to you!