Im thinking of doing a bike tour lasting several months, starting this summer. I don't know much about bicycles except for having used them as a local transportation tool, so I'm unsure of where to start.
I have a budget of 600-1200$ for the bike, the less the better as it will allow me to tour for longer. It could also be stolen so I wouldn't wanna ride around on a luxury bike.

I currently posess a 400$ bike, I think it is a hybrid bike, not sure. I've had it for 1-2 years and the parts have failed several times, so it wouldn't last long on a tour. Should I purchase a brand new bike or just buy new parts and put it on the frame of the bike that I currently have?
I'm also willing to sacrifice speed for longevity, I'm not concerned with moving from point A to B as fast a possible.

And some other questions, I've never used clipless pedals or anything, should I employ this on my bike for my tour? I don't know anything about bike mechanics, what skills should I learn so that I can face the challenges that will appear from crossing hundreds of miles on a bike continuously?