I've recently started singing after a long gap and I'm working on getting to be a floor-singer in a few clubs- that's hard enough to achieve although for me it is more about self-confidence, overcoming nerves and memory issues. These days it seems to take months to learn a song and maybe I never sing it in public at all- it's so much easier not to. There's a lot of competition out there and it's tough to get heard. Maybe my voice isn't that great either. But I am motivated- right now it seems like the only thing worth doing.
    So what to do? I think you need to be versatile. If you have a good voice that will carry you, talent will shine through and be appreciated if you persevere; otherwise you might think about developing your performance skills. If you don't play an instrument you can still extend your "act" to entertain the audience (this is all about entertaining people isn't it?) If you only have one song why not add some spiel- a little stand up comedy perhaps? There was a chap on Telly the other day (sorry there goes my memory again) who made a half hour show out of introducing a song. And if you are really serious you might want to think about ditching the wife and kids...