Great to hear your story. Good for you. A 30 mile RT commute is ambitious for sure, but you are on it! I don't have any good solutions to your tech problems beside also suggesting a local bike coop. But in the longer term picture and excuse me if this is presumptuous, but from the sound of your situation my advice would be to start saving for a new bike.
It sounds like you dig riding and commuting and you are committing to it as well. Great. Start doing research now (searching this forum is great place for info and advice). Every day while you ride your current bike think about all the things that would make it better, what are important and what are not as important. Over time you will figure out what type of bike will best suit your needs. Meanwhile dedicate all or some of the savings you are seeing from riding and not driving or using public transportation to build up a fund. It doesn't have to be a new bike, there are a lot of great used bikes out there that can be perfect.
Good luck - keep riding!