What kind of DSLR Camera Should I buy? PLZ HELP!?

Hi, I have saved up my money and I am looking to buy a new digital camera. I sell horses for a living, and need it to take some really awesome pictures. I want a DSLR camera, I want to take professional looking pictures, because the pictures sell the horses. I need something with a decent zoom, because sometimes they are across a pasture. I need something with high ISO, because a take pictures in a covered arena and round pen, and sometimes at sunset. This is the most important. Sometimes they will ride at night with just the arena lights on, and all my pictures come out blurry. I also need one that will take pictures quickly, because with horse photography, its all about timing. I will need one that I can take multiple shots quickly. I can spend about $1000. Maybe a little more if it suits me perfect. Please help, I really don't know a whole lot about cameras and I don't know about all the terminology. Thanks so much!