I had a terrible time last year finding a bathing suit that would fit right. I live in a beach town and went into almost every store here and couldn't find anything that I liked let alone would pay the money for.
I ordered a couple from VS and they were alright, I ordered a couple from Carabella and they were alright, and I ordered virtually every bathing suit out of the Venus catalog because I liked so many.
I eventually bought 2 out of the Venus catalog. One of them was a traditional bikini with underwire support and the other was a halter top with a bikini bottom and then I got the matching tankini top. So really I got 3 bathing suits. I love
http://www.venusswimwear.com There shipping was quick and their return policy was fantastic. One of the best things about Venus is that you can buy their bathing suits in pieces ... meaning if you have a big top and a little bottom you aren't bound to one size like a small, medium, large, 4, 6, 8,or 14. The prices aren't too offensive either.
Good luck. Shopping for a bathing suit is not an easy thing to do.