I would upgrade the service based on the little information you gave me. What stands out is the new bathroom. That room alone must have it's own dedicated circuit. Add a power tub and now you are really pushing the envelope with a 60 amp service. You could install a small sub panel, but I would not suggest you do so.
Most people upgrade to 200 amp, with a house of your size. You could go to 150 amp, but the difference in cost will be so close it would not make economical sense.
You will need a permit and someone qualified to install the service. New wire, new meter, new panel ect... Use a meter/main. Meter and load center (panel) in one enclosure. This will help you for anything you want to do outside and make any inside panel a sub panel. This is the way I do it.
Caution! Get the permit only for the service upgrade and do not mention the other projects. If you do, you will be in for a big surprise. They will make you bring everything up to code. EVERYTHING!
Take it one thing at a time. Upgrade service, then tackle the projects after this is complete. A good qualified and licensed electrician will help you with the requirements.