Gabbanelli accordions are available to purchase direct from the Gabbanelli manufacturer online. Some places such as eBay may offer second hand products.
Accordion music can be found at any mass music merchandiser such as Daddy's Junkie Music. Accordion music can also be found online on most accordion manufacturers websites.
A good place to find an accordion wall lamp is on HomeDecorators. They are a good site to use and have coupons that could save you money. If HomeDecorators is too expensive for you, then you could go on Amazon or Ebay.
One can learn the accordion by taking lessons. They could also purchase a book to help their education.