I bought this little guy and am very happy with him. I run my horns with it.
MP 301
MP-301 6V6 Mini Amplifier with Headphone Output [MP-301] - $199.99 : Musical Paradise - Audio Art


From what you've said, you may need more power. But I would say get the rig up and running then we can figure out how much power you really need for your horns.