You need to be persistent - often stores that you might not think of like Macy's, Dress Barn and other department stores often have plus size things, but just a few of them so you have to look hard. I've gotten two great denim skirts at Dress Barn of all places! Check sale racks - this time of year is good for stuff left over from the holiday push, and you have to be willing to go through the racks, but I often find inexpensive pieces that will work fine year 'round. Also, look online. There's a lot more selection online, and more and more places are designing for plus-size women. And of course, adding a belt can make a "tent' more shape-fitting, for example.

http://www.onestopplus.com/

http://www.leeleesvalise.com/

are two places that seem to have some shapely things.

I hate that some places just assume anyone ever a size 12 wants black knit garments, and sweats, as you said, that are just sad and shapeless. And capris. I do not own a single pair of capris, think they are unflattering on almost everyone, and make ya look shorter than you actually are ... why oh why do they make so many of 'em?