Lands' End!!! Check out the website first
http://www.landsend.com and see if they may have stores near where you live. (If you have never heard of Lands' End, it's very similar to LL Bean). To me it's always better to go in person and actually try the stuff on before you buy it. They have very well made swimwear/cover-ups for ladies of any size. I used to not really like their swimwear because I thought it was too plain looking but last summer they had some adorable safari print swimsuits. At the end of the summer last year I bought a one piece giraffe print swimsuit that was perfect. I bought it for my trip to Disney in Sept. I'm not pooh-sized. I'm kind of petite on top but I kind of got the booty and hips going on (I guess I have an hourglass figure?) and this swimsuit was perfect for covering my big booty!
I know they won't have the safari print stuff since it was from last season, but I know now they have this season's swimwear out, so check it out and see if you like anything. GOOD LUCK!