yes, dicks is a good place to check. so is sports authority. i would especially look at clothing from under armour. much of their stuff is aimed at larger sizes. especially because of their marketting agreements with the nfl. both men and women.

RoadRunnerSports.com has bras for nearly all sizes.  Just make sure you look at the "motion control" ratings!!!  Champion has some nice, moderately-priced bras.  I buy most of my running shorts and tops at Target in the men's department--mostly C9 stuff.  If you want UnderArmor-type stuff, Wal-Mart has generic technical underwear from Athletic Works.  They also have Starter athletic wear (men's).  Some stores have a better selection that others.  I often have to buy my shoes from RoadRunnerSports.com, because I have big feet, and some stores don't carry my size, even though they are made in larger sizes.  RRS is also less expensive than buying in the stores.  My shoes aren't popular, so they're never on sale, and never carried at places like Dick's.  I sometimes get shoes at Eastbay.com.