If you don't commit to doing the tour, life WILL get in the way and you will never do it. I and many others on this blog can attest to that. Similarly, having the absolutely perfect bike is not so important as having a reasonably comfortable one. I've seen people going cross-country on 3-speeds. If you already have a bike, take it down to the nearest shop for a tune-up. And start riding. Then, get the best possible bike for your general use. It seems to me it is more important to get back on the bike around town than getting a touring bike right now. Finally, you can look at touring - either with the first bike you get or another one.
There are many variables about touring that will affect the bike you use. Panniers or trailer? Pavement 100% of the time, rail trails, or even some dirt? Even standard frame or recumbent? Still, I think you can get a good, mid-range bike for around town that you can convert to basic touring. So find a bike that works for you today. Tomorrow will take it's course.
Best - J