I can't speak on which bike would be best for you, but a bike fitting is a must I believe as you will get a bike that fits you as oppose to making you fit a bike (hope that's clear). I suggest you find a customer service oriented bike shop that does bike fittings; they should be able to suggest a bike for you. As far as the shorts goes, yes get some with nice padding. You will see and feel the differences. Also, I find that those chamois butter (use with bike shorts) is a good investment; it helps keep chafing in your sensitive areas down and keeps friction down, too. I didn't wear a bike jersey until about this fall (only been back on the bike since June '12), but find that they definitely have its place, particularly, the wicking properties, rear pockets, lightness. I got my summer stuff in the fall and winter (huge deals). You may want to check now, but be warned they are sized for thin guys, so it be best to go into the store and try them on. I always have to go 1-2 size larger depending on the fit (i.e. tight, slim fit etc). Start easy and don't worry about those folks flying by you - keep focused on your goal(s).
Al