You can set the video size again from the Video options when you log in to WoW and turn off windows mode or enable maximise which ever you prefer.

as for the framerate open WFT > config.wft in notepad and look for

set maxfps= xxx
set bkfps = xxx

remove these and you should be back in business.... you can also set screen resolution here but it's probably just as easy to do it in game.