Have 16GB 3GS 's up to 4.3.4; can get it higher w/o jailbreaking

My title above does leave out some important info: just bought a 32GB iPhone 5 last night... and can't push any of my 14GB of data from old phone to new. =(

Have way too much data to try to manually transfer it... was hoping to update the 4.3.4 to anything that could be read by the AT&T store (so they can mirror it). Anyone have any ideas for me to try? Right now I'm carrying 2 phones: the old one for the data & the new one for calls and texts... fairly annoying.

Would really appreciate any help possible.