New to sport in Ohio

My name is Mark and I am in Columbus Ohio. I am just beginning to train for a triathalon. I lift weights 5 days a week and I ride the bike all the time. Unfortunately I bought a mountain bike and that is all that I have to ride. I am hoping to catch a cheap road bike on craigslist or something as a thousand dollar bike is way out of my budget. I am trying to run as much as possible but I am a little heavier than when I was in school and running a lot. I still have roughly 30 lbs to lose which isnt bad considering my size. I am six five with a broad shoulder and large build so it isnt too bad. I need to do something competitive and would love to train with others or do a team triathalon but I have a lot of training yet to do. Any advice on a bike or how to proceed would be greatly appreciated.