I'm a 34F also and I love the Medela underwire:
http://www.birthandbaby.com/shop/categories/52I order from the shop to which I linked. They are really great. Their site has guidelines for measuring and if you're unsure about sizing, you can call and several of the staff members are lactation consultants and they just have really great perspective. It looks like the bra was discontinued (aaack! that would be a night mare as I LOVE this bra and will be needing more for baby #3), but will be available again in January.
The other great thing about that shop is that they only charge a dollar for shipping and are fab about returns, so you can order a bunch of bras, try them, and return what you don't want (they actually encourage this!). I promise, I'm not affiliated with them, lol, I just feel your pain on the impossibility of finding a nursing bra in my size and they've been very, very helpful.