I agree with the people who said to get into training, though I'd suggest finding a program that teaches Submission Wrestling. That will work with what you know from wrestling and will add things from other arts that work in the ring. If you can't find a place that teaches that then I'd suggest BJJ or Judo (or even preferably both if you can afford it).
Also, for striking, there are tons of things you could do. There is the most popular, Muay Thai, but there is (like The Don said, TKD). Also, I don't know what style of karate you did but Kyokushin Karate is similar to Muay Thai and will teach you the striking with elbows and knees too.