At the same time, you don't need to become a better speaker. You are likely good enough right now to make a difference to your audience, to teach them something they didn't know before, or remind them of something they used to know but forget to implement.
If you have an audience available to you, Speak!
We need to find the balance between what Tony Robbins calls Constant And Never-ending Improvement, and what many call the Paralysis of Perfection. What lies between is The Action of Attainment - getting better by doing.
Spending our life learning to get better is useless if we don't put it into practice, just as doing something without learning how to do it better will rob us of attaining greater proficiency, output, and effectiveness. Don't sit on 'Ready, Set', depriving your audience of what you have to say just because its not perfect yet, but vow that the next time you speak, your message will be clearer, stronger, and more memorable - and then GO!
Its a lot easier to hide behind books, spend money of one more round of coaching or another speaking bootcamp, or settle into the warm, supportive arms of fellow Toastmasters than to go jump into the fire of a real audience. It's an eye-opening experience. All at once you'll realize you're better than you thought you were, and not as good as you could be. Sounds crazy, but those of you who've done it know exactly what I'm saying.
Yes, you need to become a better speaker. Use all the tools at hand to improve. But go out and improve in both theory and activity - imPROVE yourself on the stage itself, in front of real live people who aren't obligated to applaud when you sit down. Just do it.