It's probably not the worst thing in the world mentioning a specific group since you've only been positive so far, but I'd nip it here. Don't mention any specific details that will give anything away (colors, philanthropy, house description, president has red hair, etc.)
Feel free to think about rushing again in the spring, but I would start actively looking at other fraternities. There are probably several you just didn't get to know well enough. Although I love my sorority and can't imagine myself anywhere else, the truth is there are probably several there you'd mesh with great. If you don't find any after seriously keeping your options open and maintaining a positive attitude then you can try again. But I bet you find a home and in 6 months can't even imagine you didn't think of those guys FIRST. And give the smaller houses a shot. In formal rush they can seem invisible but can offer a lot.
Good luck!