Try the Ahh-Bras.
I am a F-G cup, and wear 2 AhhBras (one over the other) they are comfy, and give decent support.
I swear by them, but I know others who hate them so YMMV.
I'll give them a try. They can't be any worse than everything else that is out there. Thanks. 
I'm also a F cup and the AhhBra gave me absolutely no support at all.
And here I sing the praises of Freya, Elomi and Panache. I am currently an H. Yes. (Nursing mom). Normally a G. I did not know until I tried Freya that the center panel really could sit against your chest, even if you had more than an A cup. Bonus: they're pretty!
They are pricey, but worth every penny, and they LAST. Also once your get your size right there are deals to be had in Nordstrom Rack and online. Especially if you don't care about wearing last season's fabrics.
Piratelvr, straps slipping off = wrong size. If you ever make it in to B-more I have a great shop to get correctly sized.