They make these things called "derailleurs" and "cassettes" that make it so you can change gears for things like climbing.
As far as the shoes and pedals are concerned, that depends on a few things. Going on the assumption that you won't be racing this thing at a velodrome or local crit any time soon, I'd recommend getting mtn shoes. They aren't as stiff, have a smaller cleat, and often have tread, so walking small distances in them is much easier. Road shoes are just too stiff and clunky for doing any around town stuff. The clipless pedals I use are the shimano SPD dohickies. I can't remember the item numbers, but they are fairly general, and don't have much float. Hope this helped.